424B5

424B5 1 d129042d424b5.htm 424B5 424B5

Filed Pursuant to Rule 424(b)(5)
Registration No. 333- 285140

PROSPECTUS SUPPLEMENT

(To Prospectus Dated February 21, 2025)

Up to $600,000,000

LOGO

IDACORP, Inc.

Common Stock

We may issue, offer and sell up to an aggregate of $600,000,000 of our common stock, no par value (“common stock”) from time to time through BofA Securities, Inc. (“BofA Securities”), BTIG, LLC (“BTIG”), J.P. Morgan Securities LLC (“J.P. Morgan”), Mizuho Securities USA LLC (“Mizuho”), Morgan Stanley & Co. LLC (“Morgan Stanley”), MUFG Securities Americas Inc. (“MUFG”), and Wells Fargo Securities, LLC (“Wells Fargo Securities”), as our agents under an equity distribution agreement. We refer to BofA Securities, BTIG, J.P. Morgan, Mizuho, Morgan Stanley, MUFG, and Wells Fargo Securities collectively as the “sales agents.” The equity distribution agreement was entered into on May 15, 2026 (the “equity distribution agreement”). The equity distribution agreement provides that, in addition to the issuance and sale of shares of our common stock by us through the applicable sales agent, we also may enter into forward sale agreements under a separate master forward sale confirmation and related supplemental confirmation between us and such sales agent or its affiliate (except with respect to BTIG, in which case the relevant forward seller is Nomura Securities International, Inc. (acting through BTIG as its agent) for Nomura Global Financial Products, Inc. as forward purchaser) (in such capacity, each a “forward counterparty” and, collectively, the “forward counterparties”). In connection with each forward sale agreement, the relevant forward counterparty (or its affiliate) will, at our request, attempt to borrow from third parties and, through the relevant sales agent, sell a number of shares of our common stock equal to the number of shares of our common stock that underlie the forward sale agreement to hedge the forward sale agreement. We entered into master forward sale confirmations with each of the forward counterparties on May 15, 2026.

In no event will the aggregate number of shares of our common stock sold through the sales agents, as our agents and as, or on behalf of, the forward counterparties, under the equity distribution agreement have an aggregate gross sales price in excess of $600,000,000. The offering of our common stock pursuant to the equity distribution agreement will terminate upon the earliest of (1) the sale, under the equity distribution agreement, of shares of our common stock with an aggregate gross sales price equal to $600,000,000 and (2) the termination of the equity distribution agreement, pursuant to its terms, by us, the sales agents, or the forward counterparties.

We will not initially receive any proceeds from the sale of borrowed shares of our common stock by a forward counterparty or its related sales agent, as applicable. We expect to receive proceeds from the sale of shares of our common stock upon future physical settlement of the relevant forward sale agreement with the relevant forward counterparty on dates specified by us on or prior to the maturity date of the relevant forward sale agreement. If we elect to cash settle or net share settle under a forward sale agreement, we may not (in the case of cash settlement) or will not (in the case of net share settlement) receive any proceeds, and we may owe cash (in the case of cash settlement) or shares of our common stock (in the case of net share settlement) to the relevant forward counterparty.

The shares of our common stock to which this prospectus supplement relates may be offered and sold by any method permitted by law to be an “at the market offering” as defined in Rule 415 under the Securities Act of 1933, as amended (the “Securities Act”), including by means of ordinary brokers’ transactions on the New York Stock Exchange, the existing trading market for our shares of common stock, or otherwise at market prices prevailing at the time of sale, or sales made to or through a market maker or through an electronic

communications network. In addition, shares of our common stock may be offered and sold by such other methods, including privately negotiated transactions (including block trades), as we and any sales agent agree to in writing. The sales agents are not required to sell any specific number or dollar amount of shares of our common stock, but each of them and the forward counterparty, as applicable, will use its commercially reasonable efforts to sell shares designated by us in accordance with the equity distribution agreement. The sales agents will not engage in any transactions that stabilize our common stock. There is no arrangement for funds to be received in an escrow, trust or similar arrangement.

We will pay each sales agent a commission of up to 1.000% of the sales price of all shares of our common stock sold through it as our sales agent under the equity distribution agreement. The commission we pay to any sales agent for sales by privately negotiated transactions (including block trades) or other methods may vary, as we and any sales agent agree to in writing. The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental, regulatory or self-regulatory organization in connection with the sales, will be our net proceeds for the sale of the shares. In connection with each forward sale agreement, the relevant forward counterparty will receive, reflected in a reduced initial forward sale price payable by the relevant forward counterparty under its forward sale agreement, a commission of up to 1.000% of the volume weighted average of the sales prices of all borrowed shares of our common stock sold during the applicable period by it (or its related sales agent, as applicable) as a forward counterparty.

We list our common stock on the New York Stock Exchange under the symbol “IDA”. On May 14, 2026, the last reported sale price of our common stock on the New York Stock Exchange was $142.49 per share.

Investing in our common stock involves risks. See “Risk Factors” beginning on page S-8 of this prospectus supplement to read important factors you should consider before investing in our common stock.

Neither the Securities and Exchange Commission (the “SEC”) nor any other regulatory body has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.


BofA Securities	BTIG	J.P. Morgan

Mizuho	Morgan Stanley	MUFG

	Wells Fargo Securities

The date of this prospectus supplement is May 15, 2026

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT


	Page
ABOUT THIS PROSPECTUS SUPPLEMENT		S-1
FORWARD-LOOKING STATEMENTS		S-2
SUMMARY		S-5
THE OFFERING		S-6
RISK FACTORS		S-8
USE OF PROCEEDS		S-12
MATERIAL U.S. FEDERAL INCOME AND ESTATE TAX CONSIDERATIONS FOR NON-U.S. HOLDERS		S-13
PLAN OF DISTRIBUTION (CONFLICTS OF INTEREST)		S-17
WHERE YOU CAN FIND MORE INFORMATION		S-23
LEGAL MATTERS		S-25
EXPERTS		S-25

PROSPECTUS


	Page
ABOUT THIS PROSPECTUS		1
RISK FACTORS		2
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS		3
ABOUT IDACORP		6
DESCRIPTION OF COMMON STOCK		7
DESCRIPTION OF DEBT SECURITIES		10
BOOK-ENTRY SYSTEM		16
USE OF PROCEEDS		18
PLAN OF DISTRIBUTION		19
INCORPORATION OF CERTAIN INFORMATION BY REFERENCE		21
WHERE YOU CAN FIND MORE INFORMATION		22
LEGAL MATTERS		23
EXPERTS		23

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering of common stock. The second part, the accompanying prospectus, gives more general information, some of which may not apply to this offering. You should read the entire prospectus supplement, as well as the accompanying prospectus and the documents incorporated by reference that are described under “Where You Can Find More Information” in this prospectus supplement. In the event that the description of the offering varies between this prospectus supplement and the accompanying prospectus, you should rely on the information contained in this prospectus supplement. Generally, when we refer to the “prospectus,” we are referring to this prospectus supplement and the accompanying prospectus combined.

You should rely only on the information contained in this document or to which this document refers you, or in other offering materials filed by us with the SEC. This prospectus supplement, the accompanying prospectus and any free writing prospectus that we prepare or authorize contain and incorporate by reference information that you should consider when making your investment decision. We have not, and the sales agents and forward counterparties have not, authorized anyone to provide you with different information. We take no responsibility for, and can provide no assurance as to the reliability of, any different or inconsistent information. This document may only be used where it is legal to sell these securities. We are not, and the sales agents and the forward counterparties are not, making an offer of these securities in any jurisdiction where the offer is not permitted. You should not assume that the information in this prospectus supplement, the accompanying prospectus, or the documents incorporated by reference herein or therein is accurate as of any date other than the date of those documents. Our business, financial condition, results of operations, and prospects may have changed since the date of such information.

Unless we indicate otherwise, or the context otherwise requires, references in this prospectus supplement to the “Company,” “we,” “us,” and “our,” or similar terms are to IDACORP, Inc., and references in this prospectus supplement to “Idaho Power” are to Idaho Power Company, our principal operating subsidiary.

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FORWARD-LOOKING STATEMENTS

In addition to the historical information contained in this prospectus supplement, the accompanying prospectus, and the documents incorporated by reference herein, this prospectus supplement, the accompanying prospectus, and the documents incorporated by reference herein contain statements that relate to future events and expectations, such as statements regarding projected or future financial performance, power generation, cash flows, capital expenditures, regulatory filings, dividends, capital structure or ratios, load forecasts, strategic goals, challenges, objectives, and plans for future operations. Such statements constitute forward-looking statements within the meaning of Section 27A of the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), which are subject to the safe harbor created by the Private Securities Litigation Reform Act of 1995. Any statements that express, or involve discussions as to, expectations, beliefs, plans, objectives, assumptions, or future events or performance, often, but not always, through the use of words or phrases such as “anticipates,” “believes,” “could,” “estimates,” “expects,” “intends,” “potential,” “plans,” “predicts,” “preliminary,” “projects,” “targets,” “may,” “may result,” or similar expressions, are not statements of historical facts and may be forward-looking. Forward-looking statements are not guarantees of future performance, involve estimates, assumptions, risks, and uncertainties, and may differ materially from actual results, performance, or outcomes. In addition to any assumptions and other factors and matters referred to specifically in connection with such forward-looking statements, factors that could cause actual results or outcomes to differ materially from those contained in forward-looking statements include those factors discussed in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference herein and therein, and in our other filings with the SEC, including any Form 10-K, Form 10-Q, or Form 8-K incorporated by reference in this prospectus supplement or the accompanying prospectus, and in our other filings with the SEC, and we refer you to those reports for further information, as well as the following important factors:

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decisions or actions by the Idaho and Oregon public utilities commissions and the Federal Energy Regulatory Commission (“FERC”) that impact Idaho Power’s ability to recover costs and earn a return on investment;

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changes to or the elimination of Idaho Power’s regulatory cost recovery mechanisms;

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expenses and risks associated with capital expenditures and contractual obligations for, and the permitting and construction of, utility infrastructure projects that Idaho Power may be unable to complete, are delayed, have cost increases due to tariffs, supply chain constraints, or other factors, or that may not be deemed prudent by regulators for cost recovery or return on investment;

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expenses and risks associated with supplier and contractor delays and failure to satisfy project quality and performance standards on utility infrastructure projects, including as a result of tariffs, supply chain constraints, permitting requirements and limitations, and the potential impacts of those delays and failures on Idaho Power’s ability to serve customers and generate revenues;

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the rapid addition of new industrial customer load, uncertainty of forecasted power usage ramp rates or volumes, and the volatility and timing of that new load demand, resulting in increased risks of power demand potentially exceeding available supply and of revenue, cash flow, and earnings volatility;

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impacts of economic conditions, including an inflationary or recessionary environment and interest rates, on items such as operations and capital investments, supply costs and delivery delays, supply scarcity and shortages, population growth or decline in Idaho Power’s service area, changes in customer demand for electricity, revenue from sales of excess power, credit quality of counterparties and suppliers and their ability to meet financial and operational commitments and on the timing and extent of counterparties’ power usage, and collection of receivables;

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changes in residential, commercial, irrigation, and industrial growth and demographic patterns within Idaho Power’s service area, and the associated impacts on loads and load growth;

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skilled workers and third-party contractors and suppliers, the cost of living and the related impact on recruiting employees, and the ability to adjust to fluctuations in labor costs;

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changes in, failure to comply with, and costs of compliance with laws, regulations, policies, orders, federal grants, and licenses, which may result in penalties and fines, increase compliance and operational costs, and impact recovery associated with increased costs through rates;

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abnormal or severe weather conditions, wildfires, droughts, earthquakes, and other natural phenomena and natural disasters, which affect customer sales, hydropower generation, repair costs, service interruptions, public safety power shutoffs and de-energization, liability for damage caused by utility property, and the availability and cost of fuel for generation plants or purchased power to serve customers;

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advancement and adoption of self-generation, energy storage, energy efficiency, alternative energy sources, and other technologies that may reduce Idaho Power’s sale or delivery of electric power or introduce operational vulnerabilities to the power grid;

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variable hydrological conditions and over-appropriation of surface and groundwater in the Snake River Basin, which may impact the amount of power generated by Idaho Power’s hydropower facilities and power supply costs;

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ability to acquire equipment, materials, fuel, power, and transmission capacity on reasonable terms and prices, particularly in the event of unanticipated or abnormally high resource demands, price volatility (including as a result of new or increased tariffs), lack of physical availability, transportation constraints, outages due to maintenance or repairs to generation or transmission facilities, disruptions in the supply chain, or reduced credit quality or lack of counterparty and supplier credit;

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inability to timely obtain and the cost of obtaining and complying with required governmental permits and approvals, licenses, rights-of-way, and siting for transmission and generation projects and hydropower facilities;

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disruptions or outages of Idaho Power’s generation or transmission systems or of any interconnected transmission systems, which can result in liability for Idaho Power, increased power supply costs and repair expenses, and reduced revenues;

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accidents, electrical contacts, fires (either affecting or caused by Idaho Power facilities or infrastructure), explosions, infrastructure failures, general system damage or dysfunction, and other unplanned events that may occur while operating and maintaining assets, which can cause unplanned outages; reduce generating output; damage company assets, operations, or reputation; subject Idaho Power to third-party claims for property damage, personal injury, or loss of life; or result in the imposition of fines and penalties;

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acts or threats of terrorism, acts of war, social unrest, cyber or physical security attacks, and other malicious acts of individuals or groups seeking to disrupt Idaho Power’s operations or the electric power grid or compromise data, or the disruption or damage to the companies’ business, operations, or reputation resulting from such events;

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Idaho Power’s concentration in one region, and the resulting exposure to regional economic conditions and regional legislation and regulation;

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unaligned goals and positions with co-owners of Idaho Power’s existing and planned generation and transmission assets that may adversely impact Idaho Power’s ability to construct and operate those facilities in a manner most suitable to Idaho Power;

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changes in tax laws or related regulations or interpretations of applicable laws or regulations by federal, state, or local taxing jurisdictions, and the availability of expected tax credits or other tax benefits;

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ability to obtain debt and equity financing or refinance existing debt when necessary and on satisfactory terms, which can be affected by factors such as credit ratings, reputational harm, volatility or disruptions in the financial markets, interest rates, decisions by the state public utility commissions, and the companies’ past or projected financial performance;

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ability to enter into financial and physical commodity hedges with creditworthy counterparties to manage price and commodity risk for fuel, power, and transmission, and the failure of any such risk management and hedging strategies to work as intended, and the potential losses and cash flow impacts the companies may incur on those hedges;

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changes in actuarial assumptions, changes in interest rates, and the actual and projected return on plan assets for pension and other post-retirement plans, which can affect future pension and other postretirement plan funding obligations, costs, and liabilities and the companies’ cash flows;

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remediation costs associated with planned cessation of coal-fired operations at Idaho Power’s co-owned coal plants;

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ability to continue to pay dividends and achieve target dividend payout ratios based on financial performance and capital requirements, and in light of credit rating considerations, contractual covenants and restrictions, cash flows, and regulatory limitations; and

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adoption of or changes in accounting policies and principles, changes in accounting estimates, and new SEC or New York Stock Exchange (the “NYSE”) requirements or new interpretations of existing requirements.

Any forward-looking statement speaks only as of the date on which such statement is made. New factors emerge from time to time and it is not possible for us to predict all such factors, nor can we assess the impact of any such factor on the business or the extent to which any factor, or combination of factors, may cause results to differ materially from those contained in any forward-looking statement. We disclaim any obligation to update publicly any forward-looking information, whether in response to new information, future events, or otherwise, except as required by applicable law.

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SUMMARY

This summary does not contain all of the information that you should consider before investing in our common stock. You should read the following summary in conjunction with the more detailed information contained elsewhere in this prospectus supplement, the accompanying prospectus and the documents incorporated by reference in this prospectus supplement and the accompanying prospectus.

ABOUT IDACORP

We are a holding company incorporated in 1998 under the laws of the state of Idaho. Our principal operating subsidiary is Idaho Power. We are subject to the provisions of the Public Utility Holding Company Act of 2005, which provides the FERC and state utility regulatory commissions with access to books and records and imposes record retention and reporting requirements on us.

Idaho Power was incorporated under the laws of the state of Idaho in 1989 as the successor to a Maine corporation that was organized in 1915 and began operations in 1916. Idaho Power is an electric utility engaged in the generation, transmission, distribution, sale, and purchase of electric energy and capacity and is regulated by the state regulatory commissions of Idaho and Oregon and by the FERC. Idaho Power is the parent of Idaho Energy Resources Co., a joint owner of Bridger Coal Company, which mines and supplies coal to the Jim Bridger power plant owned in part by Idaho Power. Idaho Power’s utility operations constitute nearly all of our current business operations.

Our other notable subsidiaries include IDACORP Financial Services, Inc., an investor in affordable housing and other real estate tax credit investments, and Ida-West Energy Company, an operator of small hydropower generation projects that qualify under the requirements of the Public Utility Regulatory Policies Act of 1978.

Our and Idaho Power’s principal executive offices are located at 1221 W. Idaho Street, Boise, Idaho 83702, and the telephone number is (208) 388-2200.

For additional information concerning our business and affairs, including our capital requirements and external financing arrangements, and pending legal and regulatory proceedings, including descriptions of those laws and regulations to which we are subject, prospective purchasers should refer to the documents incorporated by reference into this prospectus supplement and the accompanying prospectus, as described in the section entitled “Where You Can Find More Information.”

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THE OFFERING

Common stock offered by this prospectus supplement

Shares of our common stock with an aggregate gross sales price of up to $600,000,000.

Manner of Offering

“At the market offering” that may be made from time to time through the sales agents. In addition to the issuance and sale of shares of our common stock by us through the applicable sales agents, we also may enter into forward sale agreements under separate master forward sale confirmations and related supplemental confirmations between us and the forward counterparties. In connection with each forward sale agreement, the relevant forward counterparty (or its affiliate) will, at our request, attempt to borrow from third parties and, through the relevant sales agent, sell a number of shares of our common stock equal to the number of shares of our common stock that underlie the forward sale agreement to hedge the forward sale agreement. See “Plan of Distribution (Conflicts of Interest).” In addition, shares of our common stock may be offered and sold by such other methods, including privately negotiated transactions (including block trades) as we and any sales agent agree to in writing.

Use of Proceeds

We intend to use the net proceeds that we receive upon the issuance and sale of shares of our common stock for general corporate purposes, which may include capital expenditures and the repayment of indebtedness. See “Use of Proceeds.”

We will not initially receive any proceeds from the sale of borrowed shares of our common stock by the forward counterparties (or their related sales agents, as applicable) as a hedge in connection with any forward sale agreement. We intend to use any cash proceeds that we receive upon physical settlement of any forward sale agreement, if physical settlement applies, or upon cash settlement of any forward sale agreement, if we elect cash settlement, for the purposes described above.

Listing

Our common stock is listed on the NYSE under the symbol “IDA”.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Equiniti Trust Company, LLC.

Dividend Policy

We expect to pay dividends on our common stock in amounts determined from time to time by our board of directors. Future dividend levels will be dependent on our results of operations, financial position, cash flows, and other factors.

Material U.S. Federal Income and Estate Tax Considerations for Non-U.S. Holders

Certain U.S. federal income and estate tax considerations of the acquisition, ownership, and disposition of our common stock for non-U.S. holders are described in “Material U.S. Federal Income and Estate Tax Considerations for Non-U.S. Holders” included elsewhere in this prospectus supplement.

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Risk Factors

You should read “Risk Factors” on page S-8 of this prospectus supplement, on page 2 of the accompanying prospectus, and in the documents incorporated by reference herein for a discussion of certain risks that prospective investors should consider before investing in our common stock.

Accounting Treatment

In the event that we enter into any forward sale agreement, we expect that before the issuance of shares of our common stock, if any, upon settlement of any forward sale agreement, the shares issuable upon settlement of that particular forward sale agreement will be reflected in our diluted earnings per share calculations using the treasury stock method. Under this method, the number of shares of our common stock used in calculating diluted earnings per share is deemed to be increased by the excess, if any, of the number of shares of our common stock that would be issued upon full physical settlement of that particular forward sale agreement over the number of shares of our common stock that could be purchased by us in the market (based on the average market price of our common stock during the applicable reporting period) using the proceeds receivable upon full physical settlement (based on the adjusted forward sale price at the end of the applicable reporting period). Consequently, we anticipate there will be no dilutive effect on our earnings per share except during periods when the average market price of shares of our common stock is above the then-applicable adjusted forward sale price under that particular forward sale agreement. Any issuance and delivery of our common stock by us upon any physical or net share settlement of any particular forward sale agreement, however, will result in dilution to our earnings per share.

Conflicts of Interest

The forward counterparties (or their respective affiliates) will receive the net proceeds of any sale of borrowed shares of our common stock pursuant to this prospectus supplement in connection with any forward sale agreement. Because (i) certain sales agents or their affiliates are expected to receive part of the net proceeds from the sale of shares of our common stock in connection with any forward sale agreement, and (ii) some of the net proceeds of this offering or upon settlement of any forward sale agreement may be used to repay amounts outstanding under our revolving credit facility or Idaho Power’s revolving credit facility, such sales agents would be deemed to have a conflict of interest under FINRA Rule 5121 to the extent such sales agents or affiliates receive at least 5% of the net proceeds of the offering. Any sales agent deemed to have a conflict of interest would be required to conduct the distribution of our common stock in accordance with FINRA Rule 5121. If the offering is conducted in accordance with FINRA Rule 5121, such sales agent would not be permitted to confirm a sale to an account over which it exercises discretionary authority without first receiving specific written approval from the account holder. See “Plan of Distribution (Conflict of Interest)” for additional information.

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RISK FACTORS

Investing in our common stock involves risks. Before making a decision to invest in our common stock, you should carefully consider the risks and uncertainties discussed in the following risk factors and in “Forward-Looking Statements”, as well as in “Risk Factors” and “Cautionary Note Regarding Forward-Looking Statements” in our most recently filed Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, and other filings we make from time to time with the SEC. You should also consider the risk factors described in any documents we incorporate by reference in the future. See “Where You Can Find More Information.”

The shares of our common stock offered hereby may be sold in “at the market offerings”, and investors who buy shares of our common stock at different times will likely pay different prices.

Investors who purchase shares of our common stock in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares of our common stock sold in this offering. Investors may experience a decline in the value of the shares of our common stock they purchase in this offering as a result of sales made at prices lower than the prices they paid.

It is not possible to predict the aggregate proceeds resulting from sales of our common stock made under the equity distribution agreement.

Subject to certain limitations in the equity distribution agreement and compliance with applicable law, we have the discretion to deliver a transaction confirmation to the sales agents at any time throughout the term of the equity distribution agreement. The number of shares of our common stock that are sold through the agents after delivering a transaction confirmation will fluctuate based on a number of factors, including the market price of our common stock during the sales period, the limits we set with the sales agents in any applicable transaction confirmation, and the demand for our common stock during the sales period. Because the price per share of our common stock will fluctuate during the sales period, it is not currently possible to predict the aggregate proceeds to be raised in connection with those sales.

Settlement provisions contained in a forward sale agreement subject us to certain risks.

With respect to any particular forward sale agreement we may enter into, the relevant forward counterparty will have the right to accelerate settlement of a particular forward sale agreement (or, in certain cases, the portion thereof that the relevant forward counterparty determines is affected by the relevant event) and require us to physically settle that forward sale agreement on a date specified by the relevant forward counterparty if:

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in the good faith, commercially reasonable judgment of the forward counterparty, it, or its affiliate, is unable to hedge its exposure to the transactions contemplated by its forward sale agreement because of the lack of sufficient shares of our common stock being made available for borrowing by stock lenders, or it, or its affiliate, is unable to borrow such number of shares at a rate equal to or less than an agreed maximum stock loan rate;

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we declare any dividend or distribution on shares of our common stock payable in (i) cash in excess of a specified amount (other than an extraordinary dividend), (ii) securities of another company, or (iii) any other type of securities (other than our common stock), rights, warrants, or other assets for payment (cash or other consideration) at less than the prevailing market price, as reasonably determined by the forward counterparty;

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certain ownership thresholds applicable to the forward counterparty are exceeded;

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an event is announced that, if consummated, would result in an extraordinary event (as defined in the forward sale agreement) including, among other things, certain mergers and tender offers, as well as certain events such as a delisting of our common stock (each as more fully described in the forward sale agreement); or

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certain other events of default or termination events occur, including, among other things, any material misrepresentation made by us in connection with our entry into the forward sale agreement, our bankruptcy (except as described below), or certain changes in law (each as more fully described in the forward sale agreement).

A forward counterparty’s decision to exercise its right to accelerate settlement of a particular forward sale agreement (or, in certain cases, the portion thereof that it determines is affected by the relevant event) and to require us to settle such forward sale agreement will be made irrespective of our interests, including our need for capital. In such cases, we could be required to issue and deliver shares of our common stock under the terms of the physical settlement provisions of the forward sale agreement irrespective of our capital needs, which would result in dilution to our earnings per share and may adversely affect the market price of our common stock. In addition, upon certain events of bankruptcy or insolvency relating to us, the relevant forward sale agreement will automatically terminate without further liability of either party to the agreement. Following any such termination, we would not issue any shares of our common stock and we would not receive any proceeds pursuant to the relevant forward sale agreement.

We expect that settlement of any forward sale agreement will generally occur no later than the date specified in the particular forward sale agreement. However, any forward sale agreement may be settled earlier than that specified date in whole or in part at our option. We expect that each forward sale agreement will be physically settled by delivery of shares of our common stock, unless we elect to cash settle or net share settle a particular forward sale agreement. Upon physical settlement or, if we so elect, net share settlement of a particular forward sale agreement, delivery of shares of our common stock in connection with such physical settlement or (to the extent we are obligated to deliver shares of our common stock) net share settlement will result in dilution to our earnings per share and return on equity.

In connection with any cash settlement or net share settlement, we would expect the relevant forward counterparty or its affiliates to repurchase a number of shares of our common stock equal to the portion for which we elect cash or net share settlement in order to satisfy their obligations to return the shares of our common stock the relevant forward counterparty or its affiliates had borrowed in connection with sales of our common stock under this prospectus supplement and, if applicable in connection with net share settlement, to deliver shares of our common stock to us. If the market value of our common stock at the time of the purchase is above the adjusted forward sale price at that time, we will pay or deliver, as the case may be, to the relevant forward counterparty under the relevant forward sale agreement, an amount in cash, or a number of shares of our common stock with a market value, equal to such difference. Any such difference could be significant. Conversely, if the market value of our common stock at the time of such purchase is below the forward sale price at that time, the relevant forward counterparty will pay or deliver, as the case may be, to us under the relevant forward sale agreement, an amount in cash, or a number of shares of our common stock with a market value, equal to such difference. See “Plan of Distribution (Conflicts of Interest)—Sales Through Forward Counterparties” for information on the forward sale agreements.

The forward sale price that we expect to receive upon physical settlement of a particular forward sale agreement will be subject to adjustment on a daily basis based on a floating interest rate factor equal to the overnight bank funding rate less a spread for a particular forward sale agreement and will be decreased based on amounts related to expected dividends on shares of our common stock during the term of the particular forward sale agreement. If the overnight bank funding rate is less than the spread on any day, the interest rate factor will result in a daily reduction of the applicable forward sale price for such day. The applicable forward sale price will also be subject to decrease if the cost to the forward counterparty of borrowing the number of shares of our common stock underlying the forward sale agreement exceeds a specified amount.

In addition, the purchase of shares of our common stock by any forward counterparty or its affiliates to unwind a forward counterparty’s hedge position could cause the price of our common stock to increase over time, thereby increasing the amount of cash or the number of shares of our common stock that we would owe to the relevant

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forward counterparty upon a cash settlement or net share settlement, as the case may be, of the particular forward sale agreement, or decreasing the amount of cash or the number of shares of our common stock that such forward counterparty would owe us upon cash settlement or net share settlement, as the case may be, of the particular forward sale agreement. We will not be able to control the manner in which the relevant forward counterparty unwinds its hedge position.

In certain bankruptcy or insolvency events, any forward sale agreement will automatically terminate, and we would not receive the expected proceeds from any forward sales of our common stock.

If we institute or consent to, or an appropriate regulatory or other authority institutes against us, a proceeding seeking a judgment in bankruptcy or insolvency or any other relief under any bankruptcy or insolvency law or other similar law affecting creditors’ rights or if we or such authority presents a petition for our winding up or liquidation or we consent to such a petition, any forward sale agreement that is then in effect will automatically terminate. If any such forward sale agreement so terminates under these circumstances, we would not be obligated to deliver to the relevant forward counterparty any shares of our common stock not previously delivered (or for which physical settlement has not been elected), and the relevant forward counterparty would be discharged from its obligation to pay the applicable forward sale price per share in respect of any shares of our common stock not previously settled (or for which physical settlement has not been elected). Therefore, to the extent there are any shares of our common stock with respect to which we have not elected to physically settle under the forward sale agreement at the time of the institution of or consent to any such bankruptcy or insolvency proceedings or any such petition, we would not receive the relevant forward sale price per share in respect of those shares of our common stock.

You may experience significant dilution as a result of this offering, which may adversely affect the per share trading price of our common stock.

This offering may have a dilutive effect on our earnings per share after giving effect to the issuance of our common stock in this offering and the receipt of the expected net proceeds. The actual amount of dilution from this offering, or from any future offering of our common or preferred stock, will be based on numerous factors, particularly the use of proceeds and the return generated on those proceeds, and cannot be determined at this time.

The issuance of substantial numbers of shares of common stock or securities convertible into shares of common stock, or the perception that those issuances might occur, could materially adversely affect us, including the per share trading price of shares of our common stock, and could be dilutive to our shareholders.

The vesting of equity awards granted to certain directors, executive officers and other employees under our equity incentive plans, the issuance of our common stock or securities convertible into shares of our common stock in connection with future property, portfolio, or business acquisitions, and other issuances of our common stock could have an adverse effect on the per share trading price of our common stock, and may adversely affect the terms upon which we may be able to obtain additional capital through the sale of equity securities. Any particular forward sale agreement will be physically settled, unless we elect cash or net share settlement under such forward sale agreement. If we decide to physically or net share settle any particular forward sale agreement, delivery of shares of our common stock on any physical or net share settlement of such forward sale agreement will result in dilution to our earnings per share and return on equity. In addition, future issuances of shares of our common stock may be dilutive to our shareholders.

The market price of our common stock is uncertain and may fluctuate significantly, and you could lose all or part of your investment.

Volatility in the market price and trading volume of our common stock may prevent you from being able to sell your shares at or above the price you paid for them. We cannot predict whether the market price of our common

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stock will rise or fall. Numerous factors influence the trading price of our common stock. These factors may include changes in our financial condition, results of operations and prospects, legal and administrative proceedings, and political, economic, financial, and other global and national factors that can affect the capital markets generally, the stock exchanges on which our common stock is traded, and our business segments.

Our charter and bylaws and various legal and regulatory factors could delay or prevent a change in control that you may favor.

The terms of some of the provisions in our articles of incorporation and bylaws and provisions of Idaho or Oregon law could delay or prevent a change in control that you may favor or may impede the ability of the holders of our common stock to change our management. In particular, the provisions of our articles of incorporation and bylaws:

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authorize issuance of up to 20,000,000 shares of preferred stock without further action by shareholders;

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limit the shareholders’ right to remove directors, fill vacancies, and change the number of directors;

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regulate how shareholders may present proposals or nominate directors for election at shareholders’ meetings; and

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require a supermajority vote of shareholders to amend certain provisions.

We are subject to the provisions of the Idaho Control Share Acquisition Act and the Idaho Business Combination Act, which provide for certain procedures and restrictions in connection with acquisitions or business combinations. In addition, Oregon law requires shareholders to obtain advance approval from the Oregon Public Utility Commission before acquiring 5% stock ownership in an Oregon public utility, which law Idaho Power expects to apply to it until such time, if any, as the sale of Idaho Power’s Oregon retail distribution business to Oregon Trail Electric Cooperative is consummated. Any of the above provisions could delay or prevent a change in control of Idaho Power. Even if our board of directors were to favor a sale of the company, a sale would require approval of a number of federal and state regulatory agencies, including the FERC, the Idaho Public Utilities Commission, the Oregon Public Utility Commission, and the Wyoming Public Service Commission. The approval process could be lengthy and the outcome uncertain, which may deter otherwise interested parties from proposing or attempting a business combination.

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USE OF PROCEEDS

Our credit facility consists of a revolving line of credit not to exceed the aggregate principal amount at any one time outstanding of $100 million, including swingline loans in an aggregate principal amount at any time outstanding not to exceed $10 million, and letters of credit in an aggregate principal amount at any time outstanding not to exceed $50 million. Idaho Power’s credit facility consists of a revolving line of credit, through the issuance of loans and standby letters of credit, not to exceed the aggregate principal amount at any one time outstanding of $400 million, including swingline loans in an aggregate principal amount at any time outstanding not to exceed $50 million, and letters of credit in an aggregate principal amount at any time outstanding not to exceed $50 million.

The interest rates for any borrowings under our credit facility and Idaho Power’s credit facility are based on either (1) a floating rate that is equal to the highest of the prime rate, federal funds rate plus 0.5 percent, or Term SOFR plus 1.0 percent, or 1.0 percent, or (2) the Term SOFR, plus, in each case an applicable margin, provided that the Term SOFR will not be less than 0.0 percent. If during any period the SOFR rate is unavailable or unascertainable, an alternate benchmark rate selected by the administrative agent and the borrower would apply. The applicable margin is based on our or Idaho Power’s, as applicable, senior unsecured long-term indebtedness credit rating by rating agencies, as set forth on a schedule to the credit agreements. Both our and Idaho Power’s credit facilities mature on December 6, 2030, and each contains the rights to request up to two one-year extensions, subject to certain conditions.

As of March 31, 2026, there were no borrowings outstanding under our revolving credit facility or Idaho Power’s revolving credit facility.

We will not initially receive any proceeds from the sale of borrowed shares of our common stock by the forward counterparties (or their related sales agents, as applicable) as a hedge in connection with any forward sale agreement. The relevant forward counterparties (or their respective affiliates) will receive the net proceeds of any sale of borrowed shares of our common stock sold pursuant to this prospectus supplement in connection with any forward sale agreement. We currently expect to elect full physical settlement of any relevant forward sale agreement and to use the net proceeds, if any, that we would receive upon settlement of the forward sale agreement for general corporate purposes, which may include capital expenditures and the repayment of indebtedness. If we elect to cash settle all or a portion of any forward sale agreement, we will not receive any proceeds from the sale of shares of our common stock related to such election of cash settlement of such forward sale agreement and we may either receive a cash payment from, or owe a cash payment to, the forward counterparty. If we elect to net share settle all or a portion of any relevant forward sale agreement, we will not receive any proceeds from the sale of shares of our common stock related to such election, and we may either receive shares of our common stock from, or owe shares of our common stock to, the forward counterparty. See “Plan of Distribution (Conflicts of Interest).”

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MATERIAL U.S. FEDERAL INCOME AND ESTATE TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following discussion summarizes material U.S. federal income and estate tax considerations relevant to the acquisition, ownership, and disposition of shares of our common stock applicable to Non-U.S. Holders (as defined below), and does not purport to be a complete analysis of all potential U.S. federal income tax considerations. This discussion only applies to shares of our common stock that are held as capital assets, within the meaning of Section 1221 of the Internal Revenue Code of 1986, as amended (the “Code”). This summary is based on the Code, administrative pronouncements, judicial decisions and regulations of the Treasury Department, changes to any of which subsequent to the date of this prospectus supplement may affect the tax consequences described herein (possibly with retroactive effect). This discussion does not describe all of the U.S. federal income or estate tax considerations that may be relevant to Non-U.S. Holders in light of their particular circumstances or to Non-U.S. Holders subject to special rules, such as certain financial institutions, banks, tax-exempt organizations, insurance companies, brokers, traders or dealers in securities or commodities, persons holding shares of our common stock as part of a straddle, hedge, conversion transaction, or other integrated or risk-reduction transaction, shareholders that acquired our common stock through the exercise of employee stock options or otherwise as compensation or through a tax-qualified retirement plan, persons that directly, indirectly, or constructively hold in excess of 5% of our common stock, “controlled foreign corporations,” “passive foreign investment companies,” governmental organizations, foreign tax-exempt organizations, qualified foreign pension funds (or any entities all of the interests of which are held by a qualified foreign pension fund), persons subject to the alternative minimum tax, accrual method taxpayers subject to special tax accounting rules as a result of their use of financial statements, persons deemed to sell our common stock under the constructive sale provisions of the Code, or certain former citizens or residents of the United States. This discussion does not address any U.S. federal income or estate tax consequences for any beneficial owner of shares of our common stock who is a United States person within the meaning of Section 7701(a)(30) of the Code (a “United States person”) or any entity or arrangement treated as a partnership for U.S. federal income tax purposes. Persons considering the purchase of shares of our common stock are urged to consult their tax advisors with regard to the application of the U.S. federal income tax laws to their particular situations as well as any tax consequences arising under the laws of any state, local, or foreign taxing jurisdiction. Furthermore, this discussion does not describe the effect of U.S. federal estate (except to the limited extent set forth below), generation-skipping, or gift tax laws, the Medicare tax on investment income, or the effect of any applicable non-U.S., state, or local laws.

We have not and will not seek any rulings or opinions from the Internal Revenue Service (the “IRS”) with respect to the matters discussed below. There can be no assurance that the IRS will not take a different position concerning the tax consequences of the acquisition, ownership, or disposition of shares of our common stock or that any such position would not be sustained.

Prospective investors should consult their own tax advisors with regard to the application of the U.S. federal income tax considerations discussed below to their particular situations as well as the application of any state, local, non-U.S., or other tax laws, including gift and estate tax laws.

For purposes of this summary, a “Non-U.S. Holder” means a beneficial owner of shares of our common stock that, for U.S. federal income tax purposes, is: (i) a foreign corporation or any other foreign organization classified as a corporation for U.S. federal income tax purposes, (ii) a nonresident alien individual, or (iii) a foreign estate or trust that in either case is not subject to U.S. federal income tax on a net-income basis on income from, or gain on sale of, a share of common stock. A prospective investor that is an individual may be deemed to be a resident alien, rather than a nonresident alien, by virtue of being present in the United States for at least 31 days in the calendar year and for an aggregate of at least 183 days during a three-year period ending with the current calendar year. For these purposes, all the days present in the current year, one-third of the days present in the immediately preceding year, and one-sixth of the days present in the second preceding year are counted.

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If a partnership, or other entity or arrangement treated as a partnership for U.S. federal income tax purposes, holds shares of our common stock, the tax treatment of a partner in such a partnership generally will depend upon the status of the partner and the activities of the partnership. Partners in a partnership holding shares of our common stock should consult their tax advisors as to the particular U.S. federal income and estate tax considerations relevant to the acquisition, ownership, and disposition of such shares of our common stock applicable to them.

Distributions

In general, a distribution that we make to a Non-U.S. Holder with respect to shares of our common stock will constitute a dividend for U.S. federal income tax purposes to the extent paid out of our current or accumulated earnings and profits as determined under the Code. To the extent the amount of a distribution exceeds our current and accumulated earnings and profits, such excess will constitute a return of capital and will first reduce the Non-U.S. Holder’s adjusted tax basis in our common stock, but not below zero, and then will be treated as gain from the sale of our common stock (see “—Sale or Other Taxable Disposition of Our Common Stock” below). Subject to the discussions below under “—Information Reporting and Backup Withholding” and “—Foreign Account Tax Compliance Act,” dividends paid to a Non-U.S. Holder that are not effectively connected with the Non-U.S. Holder’s conduct of a trade or business within the United States, or not attributable to a permanent establishment maintained by such Non-U.S. Holder within the United States under an applicable income tax treaty, generally will be subject to U.S. federal withholding tax at a rate of 30% of the gross amount of the dividends (unless such dividend is eligible for a reduced rate under an applicable income tax treaty). In order to obtain a reduced rate of withholding, a Non-U.S. Holder generally is required to provide to the applicable withholding agent an IRS Form W-8BEN, IRS Form W-8BEN-E, or another appropriate version of IRS Form W-8 (or a suitable substitute form) properly certifying such Non-U.S. Holder’s eligibility for the reduced rate. Non-U.S. Holders that do not timely provide the applicable withholding agent with the required certification, but that qualify for a reduced withholding rate, may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for a refund with the IRS. Non-U.S. Holders considering the purchase of shares of our common stock are urged to consult their tax advisors regarding their entitlement to any benefits under an applicable income tax treaty and the timing and manner of claiming the benefits.

Subject to the discussions below under “—Information Reporting and Backup Withholding” and “—Foreign Account Tax Compliance Act,” dividends that are effectively connected with a Non-U.S. Holder’s conduct of a trade or business in the United States and, if an applicable income tax treaty so requires, are attributable to a permanent establishment maintained by the Non-U.S. Holder in the United States, are taxed on a net-income basis at the regular graduated rates applicable to United States persons. The Non-U.S. Holder generally is required to provide to the applicable withholding agent a properly executed IRS Form W-8ECI (or a suitable substitute form) in order to claim an exemption from, or reduction in, U.S. federal withholding. In addition, a “branch profits tax” may be imposed at a 30% rate (or a reduced rate under an applicable income tax treaty) on a foreign corporation’s effectively connected earnings and profits for the taxable year, as adjusted for certain items.

Sale or Other Taxable Disposition of Our Common Stock

Subject to the discussions below under “—Information Reporting and Backup Withholding” and “ —Foreign Account Tax Compliance Act,” a Non-U.S. Holder generally will not be subject to U.S. federal income tax with respect to gain, if any, recognized on the sale or other taxable disposition of shares of our common stock, unless (i) the gain is effectively connected with the conduct by such Non-U.S. Holder of a trade or business within the United States, and, if required by an applicable income tax treaty, is attributable to a permanent establishment maintained by such Non-U.S. Holder within the United States, (ii) in the case of a Non-U.S. Holder that is an individual, such Non-U.S. Holder is present in the United States for 183 or more days in the taxable year of the disposition and certain other conditions are satisfied, or (iii) our common stock constitutes a U.S. real property interest by reason of our status as a U.S. real property holding corporation (a “USRPHC”) for U.S. federal income tax purposes.

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In the case described in (i) above, gain or loss recognized on the disposition of shares of our common stock generally will be subject to U.S. federal income taxation in the same manner as if such gain or loss were recognized by a United States person, and, in the case of a Non-U.S. Holder that is a foreign corporation, may also be subject to the branch profits tax at a rate of 30% (or a lower applicable treaty branch profits tax rate). In the case described in (ii) above, the Non-U.S. Holder will be subject to a 30% tax (or a lower applicable income tax treaty rate) on any capital gain recognized on the disposition of shares of our common stock (after being offset by certain U.S.-source capital losses).

We have not made an assessment of whether we are a USRPHC; however, even if we are a USRPHC, so long as shares of our common stock continue to be regularly traded on an established securities market in the United States, within the meaning of applicable Treasury regulations, a Non-U.S. Holder will not be subject to U.S. federal income tax on the disposition of shares of our common stock if the Non-U.S. Holder has not held more than 5% (directly, indirectly or constructively) of our total outstanding common stock at any time during the shorter of the five-year period preceding the date of disposition, or such Non-U.S. Holder’s holding period. If we are a USRPHC and our common stock were not considered to be regularly traded on an established securities market in the United States, such Non-U.S. Holder (regardless of the percentage of shares of our common stock owned) would be subject to U.S. federal income tax on a taxable disposition of shares of our common stock at the regular graduated rates applicable to United States persons and a 15% withholding tax would apply to the gross proceeds from such disposition. Non-U.S. Holders considering the purchase of shares of our common stock are urged to consult their tax advisors regarding the application of these rules.

Information Reporting and Backup Withholding

We must report annually to the IRS and to each Non-U.S. Holder the amount of any distributions paid to such holder, whether or not the distribution represents a taxable dividend, the name and address of the recipient and any tax withheld with respect to such dividends, regardless of whether withholding was required. Copies of the information returns reporting such dividends and withholding also may be made available to the tax authorities in the country in which the Non-U.S. Holder resides under the provisions of an applicable tax treaty.

A Non-U.S. Holder may be subject to backup withholding for dividends paid to such holder unless such holder certifies on IRS Form W-8BEN, IRS Form W-8BEN-E, or another appropriate version of IRS Form W-8 (or a suitable substitute form) that it is a Non-U.S. Holder (and the payor does not have actual knowledge or reason to know that such holder is a United States person), or such holder otherwise establishes an exemption.

Information reporting and, depending on the circumstances, backup withholding may apply to the proceeds of a sale of our common stock by a Non-U.S. Holder within the United States or conducted through certain U.S.-related financial intermediaries, unless the beneficial owner certifies on IRS Form W-8BEN, IRS Form W-8BEN-E, or another appropriate version of IRS Form W-8 (or a suitable substitute form) that it is a Non-U.S. Holder (and the withholding agent does not have actual knowledge or reason to know that the beneficial owner is a United States person), or such owner otherwise establishes an exemption.

Backup withholding is not an additional tax. Any amounts withheld under the backup withholding rules may be allowed as a refund or a credit against a Non-U.S. Holder’s U.S. federal income tax liability provided the required information is timely furnished to the IRS.

Foreign Account Tax Compliance Act

Sections 1471 to 1474 of the Code and related IRS guidance (commonly referred to as the Foreign Account Tax Compliance Act (“FATCA”)) impose a 30% U.S. withholding tax on any dividends on our common stock and (subject to proposed Treasury regulations discussed below) on the gross proceeds from a disposition of our common stock, in each case, if paid to a “foreign financial institution” or a “non-financial foreign entity” (including, in some cases, when such foreign financial institution or entity is acting as an intermediary), unless

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(i) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments, and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners), (ii) in the case of a non-financial foreign entity, such entity certifies that it does not have any substantial U.S. owners or provides the withholding agent with a certification (generally on an IRS Form W-8BEN, IRS Form W-8BEN-E, or another appropriate version of IRS Form W-8) identifying the direct and indirect substantial U.S. owners of the entity, or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules and provides appropriate documentation (such as an IRS Form W-8BEN-E). Although withholding under FATCA would have applied to payments of gross proceeds from the taxable disposition of our common stock on or after January 1, 2019, proposed Treasury regulations eliminate FATCA withholding on payments of gross proceeds entirely. Taxpayers generally may rely on these proposed Treasury regulations until final Treasury regulations are issued. Intergovernmental agreements governing FATCA between the United States and certain other countries may modify the foregoing requirements for certain holders of our common stock. Prospective investors should consult their own tax advisors regarding FATCA and whether it may be relevant to the ownership and disposition of shares of our common stock.

Federal Estate Tax

Shares of our common stock beneficially owned by an individual who is not a citizen or resident of the United States (as defined for U.S. federal estate tax purposes) at the time of death generally will be includable in the decedent’s gross estate for U.S. federal estate tax purposes unless an applicable income tax treaty provides otherwise.

The preceding discussion of material U.S. federal income and estate tax considerations is for general information only. It is not tax advice. Prospective investors should consult their own tax advisors regarding the particular U.S. federal, state and local and non-U.S. tax consequences of acquiring, owning and disposing of our common stock, including the consequences of any proposed changes in applicable laws.

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PLAN OF DISTRIBUTION (CONFLICTS OF INTEREST)

We entered into an equity distribution agreement on May 15, 2026 with each of the sales agents and forward counterparties. Under the terms of the equity distribution agreement we may issue and sell from time to time during the term of such agreement shares of our common stock having an aggregate gross sales price of up to $600,000,000 through the sales agents acting as our agents. Further, the equity distribution agreement provides that, in addition to the issuance and sale of shares of our common stock by us through the applicable sales agent, we may request that such sales agent, as or on behalf of a forward counterparty, use commercially reasonable efforts to sell, from time to time, shares of our common stock borrowed by the applicable forward counterparty (or its affiliates) in connection with one or more forward sale agreements as described below. In no event will the aggregate number of shares of our common stock sold through the sales agents, each as an agent for us and as or on behalf of a forward counterparty, under the equity distribution agreement have an aggregate gross sales price in excess of $600,000,000. We entered into master forward sale confirmations with each of the forward counterparties on May 15, 2026.

The shares of our common stock to which this prospectus supplement relates may be offered and sold by any method permitted by law to be an “at the market offering” as defined in Rule 415 under the Securities Act, including by means of ordinary brokers’ transactions on the NYSE, the existing trading market for our shares of common stock, or sales made to or through a market maker or through an electronic communications network. In addition, shares of our common stock may be offered and sold by such other methods, including privately negotiated transactions (including block trades), as we and any sales agent agree to in writing. The sales agents are not required to sell any specific number or dollar amount of shares of our common stock, but each of them and the forward counterparty (or its related sales agent), as applicable, will use its commercially reasonable efforts to sell shares designated by us in accordance with the equity distribution agreement. Neither we nor the sales agents will engage in any transactions that stabilize our common stock. There is no arrangement for funds to be received in an escrow, trust, or similar arrangement.

We estimate that the total initial expenses for the offering, excluding compensation payable under the equity distribution agreement, will be approximately $450,000, and we expect to incur additional expenses (in addition to any such commissions and expense reimbursement) in the future. We have agreed to reimburse the sales agents for certain reasonable documented out-of-pocket expenses, including the reasonable fees, disbursements and expenses of their counsel, in the amount of up to $150,000 in connection with entering into the equity distribution agreement and performing their obligations thereunder.

In connection with the sale of our common stock as contemplated in this prospectus supplement, the sales agents may be deemed to be “underwriters” within the meaning of the Securities Act, and the compensation paid to a sales agent may be deemed to be underwriting commissions or discounts. We have agreed to indemnify the sales agents and the forward counterparties against certain liabilities, including liabilities under the Securities Act, or to contribute to payments which they may be required to make in that respect.

We intend to report to the SEC at least quarterly (1) the number of shares of our common stock sold through the sales agents in connection with at-the-market sales as described below under “—Sales Through Sales Agents,” (2) the number of borrowed shares of our common stock sold by the forward counterparties in connection with forward sale agreements as described below under “—Sales Through Forward Counterparties” and (3) the net proceeds received by us and the compensation paid by us to the sales agents in connection with transactions described in clauses (1) and (2).

Sales of our common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as may be agreed upon. The offering of our common stock pursuant to the equity distribution agreement will terminate upon the earliest of (1) the sale, under the equity distribution agreement, of shares of our common stock with an aggregate gross sales price equal to

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$600,000,000 and (2) the termination of the equity distribution agreement, pursuant to its terms, by us, the sales agents (with respect to each of their own rights and obligations thereunder), or the forward counterparties (with respect to each of their own rights and obligations thereunder).

Sales Through Sales Agents

From time to time during the term of the equity distribution agreement, and subject to the terms and conditions set forth therein, we may deliver instructions to any of the sales agents regarding a proposed sale of shares of our common stock. We will submit orders to only one sales agent relating to the sale of shares of the common stock on any given day. Upon receipt of instructions from us, and subject to the terms and conditions of the equity distribution agreement, the applicable sales agent will use its commercially reasonable efforts to sell the amount of shares of our common stock specified in our instructions. We or the relevant sales agent may suspend the offering of shares of our common stock at any time upon proper notice to the other party, at which time the selling period will immediately terminate. Settlement for sales of shares of our common stock will occur on the first trading day following the date on which the sales were made. The obligation of the applicable sales agent under the equity distribution agreement to sell shares of our common stock pursuant to our instructions is subject to a number of conditions, which each sales agent reserves the right to waive in its sole discretion. There is no arrangement for funds to be received in an escrow, trust, or similar arrangement. In addition, shares of our common stock may be offered and sold by such other methods, including privately negotiated transactions (including block trades), as we and any sales agent agree to in writing.

Each sales agent will receive from us a commission of up to 1.000 % of the gross sales price per share for any shares sold through it as our sales agent under the equity distribution agreement. The commission we pay to any sales agent for sales by privately negotiated transactions (including block trades) or other methods may vary, as we and any sales agent agree to in writing. The remaining sales proceeds, after deducting any expenses payable by us and any transaction fees imposed by any governmental, regulatory, or self-regulatory organization in connection with the sales, will be our net proceeds for the sale of such shares.

Sales Through Forward Counterparties

From time to time during the term of the equity distribution agreement, and subject to the terms and conditions set forth therein, we may enter into one or more forward sale agreements with the applicable forward counterparty. In connection with each such forward sale agreement, we will deliver to the applicable forward counterparty related instructions requesting that the applicable forward counterparty (or its related sales agent, as applicable) execute sales of borrowed shares of our common stock.

Upon their receipt and acceptance, such forward counterparty (or its affiliates) will attempt to borrow, and such forward counterparty (or its related sales agent, as applicable) will use commercially reasonable efforts to sell, the relevant shares of our common stock to hedge such forward counterparty’s exposure under that particular forward sale agreement. We or such forward counterparty may immediately suspend the offering of our common stock at any time upon proper notice to the other.

In no event will we be party to outstanding forward sale agreements with more than one forward counterparty at any given time or party to more than one forward sale agreement with the same forward counterparty at any given time unless such forward counterparties (or their related sales agents, as applicable) would not be selling shares of our common stock simultaneously, and such forward counterparties would not be required to unwind their respective hedges of shares of our common stock at any time that such forward counterparties (or their related sales agents, as applicable) are selling shares of our common stock. Additionally, in no event may we sell shares directly at any given time when we are a party to outstanding forward sale agreements unless the related forward counterparties (or their related sales agents, as applicable) would not then be selling shares of our common stock and such forward counterparties would not then be required to unwind their respective hedges of shares of our common stock.

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We expect that such settlement will generally occur on the first trading day following each date such sales are made, unless another date shall be agreed to by the relevant parties. The obligation of the relevant forward counterparty (or its related sales agent, as applicable) under the equity distribution agreement to execute such sales of our common stock is subject to a number of conditions, which each forward counterparty (or its related sales agent, as applicable) reserves the right to waive in its sole discretion.

In connection with each forward sale agreement, the relevant forward counterparty will receive, reflected in a reduced initial forward sale price payable by the relevant forward counterparty under its forward sale agreement, a commission of up to 1.000% of the volume weighted average of the sales prices of all borrowed shares of our common stock sold during the applicable period by it as a forward counterparty (or its related sales agent, as applicable). We refer to this commission rate as the forward selling commission.

The forward sale price per share under each forward sale agreement will initially equal the product of (1) an amount equal to one minus the applicable forward selling commission and (2) the volume-weighted average price per share at which the borrowed shares of our common stock were sold pursuant to the equity distribution agreement by the relevant forward counterparty (or its related sales agent, as applicable), subject to certain adjustments. Thereafter, the forward sale price will be subject to adjustment as described below.

The forward sale agreements will provide that the forward sale price, as well as the sales prices used to calculate the initial forward sale price, will be subject to increase or decrease based on a floating interest rate factor equal to the specified benchmark’s daily rate less a spread and subject to decrease by amounts related to expected dividends on our common stock during the term of the particular forward sale agreement. If the specified benchmark’s daily rate is less than the spread for a particular forward sale agreement on any day, the interest factor will result in a reduction of the applicable forward sale price for such day. If the specified benchmark’s daily rate decreases below the spread for a particular forward sale agreement and does not subsequently increase above such spread, we may receive less than the initial forward sale price per share upon physical settlement of that particular forward sale agreement.

Before settlement of a particular forward sale agreement, we expect that the shares of our common stock issuable upon settlement of that particular forward sale agreement will be reflected in our diluted earnings per share using the treasury stock method. Under this method, the number of shares of our common stock used in calculating diluted earnings per share is deemed to be increased by the excess, if any, of the number of shares of our common stock that would be issued upon full physical settlement of that particular forward sale agreement over the number of shares of our common stock that could be purchased by us in the market (based on the average market price of our common stock during the relevant period) using the proceeds receivable upon full physical settlement (based on the adjusted forward sale price at the end of the relevant reporting period). Consequently, before physical or net share settlement of a particular forward sale agreement and subject to the occurrence of certain events, we anticipate there will be no dilutive effect on our earnings per share, except during periods when the average market price of our common stock is above the applicable adjusted forward sale price. However, if we decide to physically or net share settle any forward sale agreement, any delivery of shares of our common stock by us upon any physical or net share settlement of such forward sale agreement will result in dilution to our earnings per share.

Except under limited circumstances, we have the right to elect physical, cash, or net share settlement under any forward sale agreement. Although we expect to settle any forward sale agreement entirely by delivering shares of our common stock in connection with full physical settlement, we may, subject to certain conditions, elect cash settlement or net share settlement for all or a portion of our obligations under a particular forward sale agreement if we conclude that it is in our interest to do so. For example, we may conclude that it is in our interest to cash settle or net share settle a particular forward sale agreement if we have no then-current use for all or a portion of the net proceeds that we would receive upon physical settlement. In addition, subject to certain conditions, we may elect to accelerate the settlement of all or a portion of the number of shares of our common stock underlying a particular forward sale agreement.

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If we elect to physically settle any forward sale agreement by issuing and delivering shares of our common stock, we will receive an amount of cash from the relevant forward counterparty equal to the product of the forward sale price per share under that particular forward sale agreement and the number of shares of our common stock underlying the particular forward sale agreement. In the event that we elect to cash settle, the settlement amount will be generally related to (1) (a) the average of the volume-weighted average price of our common stock on each exchange business day during the relevant valuation period under the particular forward sale agreement minus (b) the applicable forward sale price; multiplied by (2) the number of shares of our common stock underlying the particular forward sale agreement subject to cash settlement. In the event we elect to net share settle, the settlement amount will be generally related to (1) (a) the weighted average price at which the relevant forward counterparty or its affiliate purchases shares of our common stock during the relevant valuation period for such settlement under that particular forward sale agreement minus (b) the applicable forward sale price; multiplied by (2) the number of shares of our common stock underlying the particular forward sale agreement subject to such net share settlement. If this settlement amount is a negative number, the relevant forward counterparty will pay us the absolute value of that amount (in the case of cash settlement) or deliver to us a number of shares of our common stock having a value equal to the absolute value of such amount (in the event of net share settlement). If this settlement amount is a positive number, we will pay the relevant forward counterparty that amount (in the case of cash settlement) or deliver to the relevant forward counterparty a number of shares of our common stock having a value equal to such amount (in the event of net share settlement). In connection with any cash settlement or net share settlement, we would expect the relevant forward counterparty or its affiliate to purchase shares of our common stock in secondary market transactions for delivery to third-party stock lenders to close out its, or its affiliate’s, hedge position in respect of that particular forward sale agreement. The purchase of shares of our common stock in connection with the relevant forward counterparty or its affiliate unwinding its hedge positions could cause the price of our common stock to increase (or prevent a decrease), thereby increasing the amount of cash we would owe to the relevant forward counterparty (or decreasing the amount of cash that the relevant forward counterparty would owe us) upon cash settlement or increasing the number of shares of our common stock that we are obligated to deliver to the relevant forward counterparty (or decreasing the number of shares of our common stock that the relevant forward counterparty is obligated to deliver to us) upon net share settlement of the particular forward sale agreement. See “Risk Factors.”

With respect to any forward sale agreement we may enter into, the relevant forward counterparty will have the right to accelerate settlement of such forward sale agreement and require us to physically settle or, if we so elect and the forward counterparty permits our election, cash settle, or net share settle on a date specified by the relevant forward counterparty if:

•

in the good faith, commercially reasonable judgment of the forward counterparty, it, or its affiliate is unable to hedge its exposure to the transactions contemplated by its forward sale agreement because of the lack of sufficient shares of our common stock being made available for borrowing by stock lenders or it, or its affiliate, is unable to borrow such number of shares at a rate equal to or less than an agreed maximum stock loan rate;

•

certain ownership thresholds applicable to the forward counterparty are exceeded;

•

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•

A forward counterparty’s decision to exercise its right to accelerate settlement of a particular forward sale agreement (or, in certain cases, the portion thereof that it determines is affected by the relevant event) and to require us to settle such forward sale agreement will be made irrespective of our interests, including our need for capital. In such cases, we could be required to issue and deliver shares of our common stock under the terms of the physical settlement provisions of the forward sale agreement irrespective of our capital needs, which would result in dilution to our earnings per share and may adversely affect the market price of our common stock. In addition, upon certain events of bankruptcy or insolvency relating to us, the forward sale agreement will automatically terminate without further liability of either party to the agreement. Following any such termination, we would not issue any shares of our common stock and we would not receive any proceeds pursuant to the forward sale agreement. See “Risk Factors.”

No Public Offering Outside of the United States

No action has been or will be taken in any jurisdiction (except in the United States) that would permit a public offering of the shares of our common stock, or the possession, circulation, or distribution of this prospectus supplement or the accompanying prospectus or any other material relating to us or the shares of our common stock, in any jurisdiction where action for that purpose is required. Accordingly, the shares of our common stock offered by this prospectus supplement and the accompanying prospectus may not be offered or sold, directly or indirectly, and this prospectus supplement, the accompanying prospectus and any other offering material or advertisements in connection with the shares of our common stock may not be distributed or published, in or from any country or jurisdiction except in compliance with any applicable rules and regulations of any such country or jurisdiction.

Certain Relationships

Each sales agent, each forward counterparty, and their respective affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing, and brokerage activities. Certain of the sales agents, forward counterparties, and their respective affiliates have acted and/or are acting as lenders to, and/or have from time to time performed and/or are performing, and may in the future engage in, certain investment banking, advisory, general financing, commercial banking, and other commercial transactions and services in the ordinary course of business with us or our affiliates for which they have received and, in the future, may receive customary fees and expenses. For instance, an affiliate of Wells Fargo Securities serves as a joint lead arranger and its affiliate serves as administrative agent and a lender, an affiliate of J.P. Morgan serves as a joint lead arranger and lender, and affiliates of BofA, Mizuho, Morgan Stanley, and MUFG serve as lenders under our $100 million revolving credit facility and Idaho Power’s $400 million revolving credit facility. The sales agents and their affiliates may, from time to time, engage in other transactions with or perform other services for us and our affiliates in the ordinary course of their business for which they receive customary fees and expenses.

In addition, in the ordinary course of their various business activities, the sales agents, forward counterparties and their respective affiliates, officers, directors, and employees may purchase, sell, or hold a broad array of investments and actively trade securities, derivatives, loans, commodities, currencies, credit default swaps, and other financial instruments (including bank loans) for their own account and for the accounts of their customers, and such investment and trading activities may involve or relate to assets, securities, or instruments of ours (directly, as collateral securing other obligations or otherwise) or persons and entities with relationships with us. Certain of the sales agents, forward counterparties, or their respective affiliates that have a lending relationship with us routinely hedge, and certain others of those sales agents, forward counterparties, or their respective

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affiliates may hedge, their credit exposure to us consistent with their customary risk management policies. Typically, such sales agents, forward counterparties, and their respective affiliates would hedge such exposure by entering into transactions which consist of either the purchase of credit default swaps or the creation of short positions in our securities, including potentially the shares offered hereby. Any such credit default swaps or short positions could adversely affect the future trading prices of the shares offered hereby. The sales agents, forward counterparties, and their respective affiliates may also communicate independent investment recommendations, market color, or trading ideas, or publish or express independent research views in respect of such assets, securities, or financial instruments and may at any time hold, or recommend to clients that they should acquire, long and/or short positions in such assets, securities, and instruments.

Conflicts of Interest

The forward counterparties (or their respective affiliates) will receive the net proceeds of any sale of borrowed shares of our common stock pursuant to this prospectus supplement in connection with any forward sale agreement. In addition, affiliates of certain of the sales agents are lenders under our revolving credit facility or Idaho Power’s revolving credit facility. To the extent that we use the net proceeds from this offering or upon settlement of any forward sale agreement to repay amounts we have borrowed or may borrow or re-borrow in the future under our revolving credit facility or Idaho Power’s revolving credit facility, these lenders will receive their pro rata portions of such proceeds. Because (i) certain sales agents or their affiliates are expected to receive part of the net proceeds from the sale of shares of our common stock in connection with any forward sale agreement, and (ii) some of the net proceeds of this offering or upon settlement of any forward sale agreement may be used to repay amounts outstanding under our revolving credit facility or Idaho Power’s revolving credit facility, such sales agents would be deemed to have a conflict of interest under FINRA Rule 5121 to the extent such sales agents or affiliates receive at least 5% of the net proceeds of the offering. Any sales agent deemed to have a conflict of interest would be required to conduct the distribution of our common stock in accordance with FINRA Rule 5121. If the offering is conducted in accordance with FINRA Rule 5121, such sales agent would not be permitted to confirm a sale to an account over which it exercises discretionary authority without first receiving specific written approval from the account holder.

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WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements, and other information with the SEC. Our SEC filings are available to the public over the Internet at the SEC’s website at www.sec.gov. Information about us is also available at our website at idacorpinc.com. However, the information accessible on or through our website is not a part of this prospectus supplement.

This prospectus supplement and the accompanying prospectus, which include information incorporated by reference, are part of a registration statement we have filed with the SEC. As permitted by the SEC’s rules, this prospectus supplement and the accompanying prospectus do not contain all of the information included in the registration statement and the accompanying exhibits and schedules we file with the SEC. You should read the registration statement and the exhibits and schedules for more complete information about us and our common stock.

The SEC allows us to incorporate by reference information into this prospectus supplement and the accompanying prospectus, which means that we can disclose important information to you by referring you to other documents filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus. We incorporate by reference the following documents that we filed with the SEC (SEC file number 1-14465):

•

Annual Report on Form 10-K for the year ended December 31, 2025, filed on February 19, 2026;

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The information specifically incorporated by reference into our Annual Report on Form 10-K from our Definitive Proxy Statement on Schedule 14A, filed with the SEC on April 2, 2026;

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Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, filed on April 30, 2026; and

•

Description of our common stock contained in Exhibit 4.9 of our Annual Report on Form 10-K for the year ended December 31, 2025, and any amendment or report filed for the purpose of updating such description.

We also incorporate by reference all documents we subsequently file pursuant to Sections 13(a), 13(c), 14, or 15(d) of the Exchange Act, after the date of this prospectus, and before we terminate the offering.

We are not incorporating by reference any documents or portions of documents that are not deemed filed with the SEC, including any information furnished pursuant to Items 2.02 or 7.01 of Form 8-K. Any statement contained in a document incorporated or deemed to be incorporated by reference in or deemed to be part of this prospectus supplement or the accompanying prospectus shall be deemed to be modified or superseded for purposes of this prospectus supplement or the accompanying prospectus to the extent that a statement contained in any other subsequently filed document which also is or is deemed to be incorporated by reference or deemed to be part of this prospectus supplement or the accompanying prospectus modifies or replaces such statement. Any statement contained in a document that is deemed to be incorporated by reference or deemed to be part of the prospectus after the most recent effective date may modify or replace existing statements contained in this prospectus supplement or the accompanying prospectus. Any such statement so modified or superseded shall not be deemed in its unmodified form to constitute a part of this prospectus supplement or the accompanying prospectus for purposes of the Securities Act.

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We will provide to each person, including any beneficial owner, to whom this prospectus supplement and accompanying prospectus is delivered, a copy of any or all of the information that has been incorporated by reference in this prospectus supplement and the accompanying prospectus but not delivered with this prospectus supplement and the accompanying prospectus. You may obtain a copy of this information at no cost by written or oral request to us at the following address:

Shareowner Services

IDACORP, Inc.

1221 W. Idaho Street

Boise, ID 83702

Telephone (208) 388-2200

You may also access these documents at our website at www.idacorpinc.com.

You should rely only on information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not authorized any other person to provide you with different information. We are not making an offer to sell the securities offered hereby in any jurisdiction where the offer or sale is not permitted.

The information contained in or incorporated by reference in this prospectus supplement and the accompanying prospectus is accurate only as of the date of the respective documents in which the information is contained. Our business, financial condition, results of operations, and prospects may have changed since those dates.

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LEGAL MATTERS

The validity of the common stock offered hereby and certain other related legal matters will be passed upon for IDACORP by Julia A. Hilton, Vice President and General Counsel of IDACORP, and Perkins Coie LLP, Seattle, Washington. The validity of the common stock offered hereby will be passed upon for the sales agents by Sullivan & Cromwell LLP, Los Angeles, California. Certain legal matters will be passed upon for any forward counterparties by Simpson Thacher & Bartlett LLP. Sullivan & Cromwell LLP may, for matters governed by the laws of the state of Idaho, rely upon the opinion of Ms. Hilton. Ms. Hilton owns shares of vested and unvested restricted common stock of IDACORP acquired pursuant to employee benefit plans and participates in various employee benefit plans offered to employees of IDACORP and Idaho Power Company.

EXPERTS

The financial statements of IDACORP, Inc. as of December 31, 2025 and 2024, and for each of the three years in the period ended December 31, 2025, incorporated by reference in this prospectus supplement and the effectiveness of IDACORP’s internal control over financial reporting, have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports. Such financial statements are incorporated by reference in reliance upon the reports of such firm given their authority as experts in accounting and auditing.

With respect to the unaudited interim financial information for the periods ended March 31, 2026 and 2025, which is incorporated by reference herein, Deloitte & Touche LLP, an independent registered public accounting firm, have applied limited procedures in accordance with the standards of the Public Company Accounting Oversight Board (United States) for a review of such information. However, as stated in their reports included in IDACORP’s Quarterly Report on Form 10-Q for the quarter ended March 31, 2026 and incorporated by reference herein, they did not audit and they do not express an opinion on that interim financial information. Accordingly, the degree of reliance on their reports on such information should be restricted in light of the limited nature of the review procedures applied. Deloitte & Touche LLP is not subject to the liability provisions of Section 11 of the Securities Act for their reports on the unaudited interim financial information because those reports are not “reports” or a “part” of the registration statement prepared or certified by an accountant within the meaning of Sections 7 and 11 of the Securities Act.

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PROSPECTUS

LOGO

COMMON STOCK

DEBT SECURITIES

We may offer from time to time, in one or more series:

•

our common stock, and

•

our debt securities.

We may offer these securities in any combination in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. Before you invest, you should carefully read this prospectus and any supplements, as well as the information that we incorporate by reference in this prospectus.

We may offer these securities directly or through underwriters, agents or dealers, as described in the “Plan of Distribution.” The supplements to this prospectus will describe the terms of any particular plan of distribution, including any underwriting arrangements.

We list our common stock on the New York Stock Exchange under the symbol “IDA”. On February 20, 2025, the closing price on the New York Stock Exchange for our common stock was $112.72.

Our principal executive offices are located at 1221 West Idaho Street, Boise, Idaho 83702-5627, and our telephone number is (208) 388-2200.

Investing in our securities involves risks. Please see “Risk Factors” on page 2 of this prospectus as well as the risk factors in our most recent Annual Report on Form 10-K and in any other reports we file pursuant to the Securities Exchange Act of 1934 that we incorporate by reference in this prospectus.

NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

The date of this prospectus is February 21, 2025

TABLE OF CONTENTS


	Page
About this Prospectus		1
Risk Factors		2
Cautionary Note Regarding Forward-Looking Statements		3
About IDACORP		6
Description of Common Stock		7
Description of Debt Securities		10
Book-Entry System		16
Use of Proceeds		18
Plan of Distribution		19
Incorporation of Certain Information by Reference		21
Where You Can Find More Information		22
Legal Matters		23
Experts		23

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement on Form S-3 that IDACORP, Inc. filed with the U.S. Securities and Exchange Commission (the “SEC”) using the “shelf” registration process. Under this shelf registration process, we may from time to time sell the securities described in this prospectus in one or more offerings. This prospectus provides a general description of the securities. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. That prospectus supplement may include or incorporate by reference a detailed and current discussion of risk factors and will discuss special considerations applicable to those securities. The prospectus supplement may also add, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with additional information described under “Where You Can Find More Information.” If there is any inconsistency between the information in this prospectus and any prospectus supplement, you should rely on the information contained in that prospectus supplement.

You should rely only on the information contained or incorporated by reference in this prospectus, in any accompanying prospectus supplement or in any free writing prospectus filed by us with the SEC. No person is authorized to give any information or to make any representations other than those contained or incorporated by reference in this prospectus, the applicable prospectus supplement, and the applicable pricing supplement, if any, and, if given or made, such information or representations must not be relied upon as having been authorized.

This prospectus does not constitute an offer to sell or the solicitation of an offer to buy any securities other than the securities described in this prospectus or an offer to sell or the solicitation of an offer to buy such securities in any circumstances in which such offer or solicitation is unlawful. Neither the delivery of this prospectus, the applicable prospectus supplement or any applicable pricing supplement, nor any sale made hereunder, shall under any circumstances create any implication that there has been no change in our affairs since the date of this prospectus, or that the information contained or incorporated by reference in this prospectus is correct as of any time subsequent to the date of such information.

The distribution of this prospectus, the applicable prospectus supplement and any applicable pricing supplement and the offering of the securities in certain jurisdictions may be restricted by law. This prospectus does not constitute an offer, or any invitation on our behalf, to subscribe to or purchase any of the securities, and may not be used for or in connection with an offer or solicitation by anyone, in any jurisdiction in which such an offer or solicitation is not authorized or to any person to whom it is unlawful to make such an offer or solicitation.

Unless we indicate otherwise, or the context otherwise requires, references in this prospectus to the “company,” “we,” “us” and “our” or similar terms are to IDACORP, Inc. and its consolidated subsidiaries.

RISK FACTORS

Investing in our securities involves risks. Before making a decision to invest in our securities, you should carefully consider the risks and uncertainties discussed in “Risk Factors,” “Cautionary Note Regarding Forward-Looking Statements” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the fiscal year ended December 31, 2024, which is incorporated by reference into this prospectus. You should also consider the risk factors described in any accompanying prospectus supplement or any documents we incorporate by reference in the future. See “Where You Can Find More Information.”

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus, any accompanying prospectus supplement and the documents incorporated by reference herein may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Any statements that express, or involve discussions as to, expectations, beliefs, plans, objectives, assumptions, or future events or performance, often, but not always, through the use of words or phrases such as “anticipates,” “believes,” “could,” “estimates,” “expects,” “intends,” “potential,” “plans,” “predicts,” “preliminary,” “projects,” “targets,” “may,” “may result,” or similar expressions, are not statements of historical facts and may be forward-looking. Forward-looking statements are not guarantees of future performance, involve estimates, assumptions, risks, and uncertainties, and may differ materially from actual results, performance, or outcomes. In addition to any assumptions and other factors and matters referred to specifically in connection with such forward-looking statements, factors that could cause actual results or outcomes to differ materially from those contained in forward-looking statements include those factors discussed in our filings with the SEC, including those discussed in Part I, Item 1A of the Company’s most recent Annual Report on Form 10-K under the heading “Risk Factors,” which are incorporated herein and as may be supplemented from time to time in our other filings with the SEC, as well as the following important factors:

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changes to or the elimination of Idaho Power’s regulatory cost recovery mechanisms;

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expenses and risks associated with capital expenditures and contractual obligations for, and the permitting and construction of, utility infrastructure projects that Idaho Power may be unable to complete, are delayed, or that may not be deemed prudent by regulators for cost recovery or return on investment;

•

expenses and risks associated with supplier and contractor delays and failure to satisfy project quality and performance standards on utility infrastructure projects, and the potential impacts of those delays and failures on Idaho Power’s ability to serve customers and generate revenues;

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the rapid addition of new industrial and commercial customer load and the volatility of such new load demand, resulting in increased risks and costs of power demand potentially exceeding available supply;

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the potential financial impacts of industrial customers not meeting forecasted power usage ramp rates or amounts;

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changes in residential, commercial, and industrial growth and demographic patterns within Idaho Power’s service area, and the associated impacts on loads and load growth;

•

employee workforce factors, including the operational and financial costs of unionization or the attempt to unionize all or part of the companies’ workforce, the cost and ability to attract and retain skilled workers and third-party contractors and suppliers, the cost of living and the related impact on recruiting employees, and the ability to adjust to fluctuations in labor costs;

•

changes in, failure to comply with, and costs of compliance with laws, regulations, policies, orders, and licenses, which may result in penalties and fines, increase compliance and operational costs, and impact recovery associated with increased costs through rates;

•

Idaho Power’s concentration in one industry and one region, and the resulting exposure to regional economic conditions and regional legislation and regulation;

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unaligned goals and positions with co-owners of Idaho Power’s existing and planned generation and transmission assets;

•

ability to obtain debt and equity financing or refinance existing debt when necessary and on satisfactory terms, which can be affected by factors such as credit ratings, reputational harm, volatility or disruptions in the financial markets, interest rates, decisions by the Idaho, Oregon, or Wyoming public utility commissions, and the companies’ past or projected financial performance;

•

incur on those hedges, which can be affected by factors such as the volume of hedging transactions and degree of price volatility;

•

changes in actuarial assumptions, changes in interest rates, increasing health care costs, and the actual and projected return on plan assets for pension and other post-retirement plans, which can affect future pension and other postretirement plan funding obligations, costs, and liabilities and the companies’ cash flows;

•

remediation costs associated with planned cessation of coal-fired operations at Idaho Power’s co-owned coal plants and conversion of the plants to natural gas;

•

changing market dynamics due to the emergence of day ahead or other energy and transmission markets in the western United States and surrounding regions.

Any forward-looking statement speaks only as of the date on which such statement is made. New factors emerge from time to time and it is not possible for the company to predict all such factors, nor can it assess the impact of any such factor on the business or the extent to which any factor, or combination of factors, may cause results to differ materially from those contained in any forward-looking statement. IDACORP disclaims any obligation to update publicly any forward-looking information, whether in response to new information, future events, or otherwise, except as required by applicable law.

ABOUT IDACORP

Overview

We are a holding company incorporated in 1998 under the laws of the state of Idaho. Our principal operating subsidiary is Idaho Power Company. We are subject to the provisions of the Public Utility Holding Company Act of 2005, which provides the FERC and state utility regulatory commissions with access to books and records and imposes record retention and reporting requirements on us.

Idaho Power Company was incorporated under the laws of the state of Idaho in 1989 as the successor to a Maine corporation that was organized in 1915 and began operations in 1916. Idaho Power Company is an electric utility engaged in the generation, transmission, distribution, sale, and purchase of electric energy and capacity and is regulated by the state regulatory commissions of Idaho and Oregon and by the FERC. Idaho Power Company is the parent of Idaho Energy Resources Co., a joint-owner of Bridger Coal Company, which mines and supplies coal to the Jim Bridger plant owned in part by Idaho Power Company. Idaho Power Company’s utility operations constitute nearly all of our current business operations.

Idaho Power Company provided electric utility service to approximately 649,000 retail customers in southern Idaho and eastern Oregon as of December 31, 2024. Approximately 547,000 of these customers are residential. Idaho Power’s principal commercial and industrial customers are involved in food processing, electronics and general manufacturing, agriculture, health care, government, education, and information technology. Idaho Power Company also provides irrigation customers with electric utility service to operate irrigation pumps during the agricultural growing season. Idaho Power Company holds franchises, typically in the form of right-of-way arrangements, in 71 cities in Idaho and 7 cities in Oregon and holds certificates from the respective public utility regulatory authorities to serve all or a portion of 25 counties in Idaho and 3 counties in Oregon. Idaho Power Company’s service area covers approximately 24,000 square miles with an estimated population of 1.4 million.

For additional information concerning our business and affairs, including our capital requirements and external financing arrangements, and pending legal and regulatory proceedings, including descriptions of those laws and regulations to which we are subject, prospective purchasers should refer to the documents incorporated by reference into this prospectus as described in the section entitled “Where You Can Find More Information.”

Dividends from Subsidiaries

Since we are a holding company, substantially all of our cash flow is provided by dividends paid to us by our subsidiaries, most notably Idaho Power Company. Since Idaho Power Company is a public utility, it is subject to regulation by state utility commissions and other regulatory agencies, which impose limits on investment returns or otherwise impact the amount of dividends that Idaho Power Company may declare and pay, and to a federal statutory limitation on the payment of dividends. In addition, certain agreements entered into by Idaho Power Company set restrictions on the amount of dividends it may declare and pay and restrict the circumstances under which such dividends may be declared and paid. Further, Idaho Power Company’s credit facility requires it to maintain specified leverage ratios of consolidated indebtedness to consolidated total capitalization. The specific restrictions on dividends contained in agreements to which Idaho Power Company is a party, as well as specific regulatory limitations on dividends, are described in our Forms 10-K and 10-Q, which are incorporated by reference into this prospectus.

DESCRIPTION OF COMMON STOCK

This section summarizes the material terms of our common stock. This summary is not complete. We refer you to our articles of incorporation, as amended, and our amended bylaws, each of which is on file with the SEC and which we have incorporated by reference in this prospectus. We also refer you to the laws of the state of Idaho. The prospectus supplement relating to any offering of common stock will describe the number of shares offered and the initial offering price or method of determining the initial offering price of those shares.

As used under this caption, “Description of Common Stock,” references to “we,” “us,” “our” and other similar references mean IDACORP, Inc., excluding, unless otherwise expressly stated or the context otherwise requires, its subsidiaries.

General

Authorized Shares; Listing. Our articles of incorporation, as amended, authorize us to issue 120,000,000 shares of common stock, without par value, and 20,000,000 shares of preferred stock, without par value. Our common stock is listed on the New York Stock Exchange under the trading symbol “IDA”.

Dividend Rights. Subject to the prior rights of the preferred stock, holders of our common stock are entitled to receive any dividends our board of directors may declare on the common stock. The board of directors may declare dividends from any property legally available for this purpose.

Voting Rights. The common stock has one vote per share. The holders of our common stock are entitled to vote on all matters to be voted on by shareholders. The holders of our common stock are not entitled to cumulative voting in the election of directors. Holders of our preferred stock will not have any right to vote except as established by our board of directors or as provided in our articles of incorporation or bylaws or by state law. A majority of the outstanding shares entitled to vote on a particular matter at a meeting constitutes a quorum. Action on a matter is approved if the votes cast favoring the action exceed the votes cast opposing the action, unless our articles of incorporation, the Idaho Business Corporation Act or our bylaws require a greater number of affirmative votes. A plurality of the votes cast determines the election of directors.

Liquidation Rights. Subject to the prior rights of the preferred stock, if we liquidate, dissolve or wind up, whether this is voluntary or not, the holders of our common stock will be entitled to receive any net assets available for distribution to shareholders.

Other Rights. The common stock is not liable to further calls or assessment. The holders of our common stock are not entitled to subscribe for or purchase additional shares of our capital stock. Our common stock is not subject to redemption and does not have any conversion or sinking fund provisions.

Effects on Our Common Stock If We Issue Preferred Stock. Our board of directors has the authority, without further action by shareholders, to issue up to 20,000,000 shares of preferred stock in one or more series. The board of directors has the authority to determine the terms of each series of preferred stock, within the limits of the articles of incorporation and the laws of the state of Idaho. These terms include the number of shares in a series, dividend rights, liquidation preferences, terms of redemption, conversion rights and voting rights. If we issue preferred stock, it may negatively affect the holders of our common stock. These possible negative effects include diluting the voting power of shares of our common stock and affecting the market price of our common stock. In addition, the ability of our board of directors to issue preferred stock without shareholder approval may delay or prevent a change in control of the company.

Transfer Agent and Registrar. EQ Shareowner Services is the transfer agent and registrar for the common stock.

Provisions of Our Articles of Incorporation and Our Bylaws That Could Delay or Prevent a Change in Control

Although it is not the intention of the board of directors to discourage legitimate offers to enhance shareholder value, the existence of unissued common stock, the ability of the board of directors to issue preferred stock without further shareholder action and other provisions of our articles of incorporation and bylaws may discourage transactions aimed at obtaining control of us.

Number of Directors, Vacancies, Removal of Directors. Our bylaws provide that the board of directors will have at least 9 and at most 15 directors. These restrictions on the size of the board may be changed by amendment of our bylaws, which must be approved by a two-thirds vote of shareholders entitled to vote, or by a majority vote of the board of directors. A majority of the board decides the exact number of directors at a given time. The board fills any new directorships it creates and any vacancies. Also, directors may be removed by the shareholders only for cause and only if at least two-thirds of the shares of our outstanding voting stock approve the removal. These provisions may delay or prevent a shareholder from gaining control of the board.

Meetings of Shareholders

Calling of a Special Meeting. The president, a majority of the board of directors or the chair of the board may call a special meeting of the shareholders at any time. Holders of at least 20% of the outstanding shares entitled to vote may call a special meeting if such holders sign, date and deliver to our secretary one or more written demands describing the purpose(s) of the proposed meeting, as well as documentation of the shareholders’ ownership percentage and information regarding the shareholders’ proposal. Upon receipt of one or more written demands from such holders, our secretary is responsible for determining whether such demand or demands conform to the requirements of the Idaho Business Corporation Act, our articles of incorporation and our bylaws. After making an affirmative determination, our secretary will prepare, sign and deliver the notices for such meeting. The shareholders may suggest a time and place in their demand(s), but the board of directors will determine the time and place of any such meeting by resolution. These provisions for calling a special meeting may delay or prevent a person from bringing matters before a shareholder meeting.

No Cumulative Voting. Our articles of incorporation do not provide for cumulative voting in the election of directors. This could prevent directors from being elected by a relatively small group of shareholders.

Advance Notice Provisions. Our bylaws require that for a shareholder to nominate a director or bring other business before an annual meeting, the shareholder must give notice and provide other information called for by our bylaws, including with respect to Rule 14a-19, to our secretary not later than the close of business on the 120th day nor earlier than the close of business on the 150th day prior to the first anniversary of the date of the preceding year’s annual meeting. If the date of the annual meeting is more than 30 days before or 60 days after the anniversary date of the preceding year’s annual meeting or if no annual meeting was held in the preceding year, the shareholder must deliver notice no earlier than the close of business on the 150th day prior to the date of such annual meeting and not later than the close of business on the later of the 120th day prior to the date of such annual meeting or, if the first public announcement of the date of such annual meeting is less than 130 days prior to the date of such annual meeting, the 10th day following the day on which we first publicly announce the date of such meeting. Our bylaws also limit business at a special meeting to the purposes stated in the notice of the special meeting, subject to the introduction of additional business at the discretion of the board of directors. These advance notice provisions may delay a shareholder from bringing matters before a shareholder meeting. The provisions may provide enough time for our board of directors to begin litigation or take other steps to respond to these matters, or to prevent them from being acted upon, if our board of directors finds it necessary or desirable for any reason.

Amendment of Articles of Incorporation. Our articles of incorporation require an 80% vote of shareholders entitled to vote in order to amend the provisions relating to the board of directors and the amendment of our articles of incorporation, unless such amendment is recommended by two-thirds of the continuing directors, as defined.

Amendment of Bylaws. Amendment of the bylaws relating to the board of directors or advance notice provisions for shareholder meetings requires a two-thirds vote of shareholders entitled to vote or a majority vote of the board of directors.

Provisions of Idaho Law That Could Delay or Prevent a Change in Control

Idaho Control Share Acquisition Law. We are subject to the provisions of the Idaho Control Share Acquisition Law. This law is designed to protect minority shareholders in the event that a person acquires or proposes to acquire shares of voting stock giving it at least 20%, at least 33 1/3%, or more than 50% of the voting power in the election of our directors. Under this law, an acquiring person must deliver to us an information statement that includes, most notably, the acquiring person’s identity, its acquisition plans and its financing. The acquiring person cannot vote the shares it holds that are greater than the applicable percentages unless two-thirds of the outstanding voting stock, excluding shares owned by the acquiring person, approves the exercise of such voting power. If the acquiring person so requests and complies with other requirements, we must hold a special meeting within 55 days of receiving the information statement from the acquiring person for the shareholders to vote. If the acquiring person does not deliver the information statement, or our shareholders do not approve such voting power, we may redeem all of the acquiring person’s shares that exceed the applicable percentage at their fair market value.

Idaho Business Combination Law. We are also subject to the Idaho Business Combination Law. This law prohibits us from engaging in certain business combinations with a person who owns 10% or more of our outstanding voting stock for a three-year period after the person acquires the shares. This prohibition does not apply if our board of directors approved of the business combination or the acquisition of our shares before the person acquired 10% of the shares. After the three-year period, we could engage in a business combination with the person only if two-thirds of our outstanding voting stock, excluding shares owned by the person, approve, or the business combination meets minimum price requirements.

DESCRIPTION OF DEBT SECURITIES

As used under this caption, “Description of Debt Securities,” references to “we,” “us,” “our” and other similar references mean IDACORP, Inc., excluding, unless otherwise expressly stated or the context otherwise requires, its subsidiaries.

General

We will issue the debt securities offered in this prospectus under our senior debt securities indenture, dated as of February 1, 2001. Deutsche Bank Trust Company Americas, formerly known as Bankers Trust Company, is the trustee under the indenture. We may amend and supplement the indenture and will supplement it by one or more supplemental indentures relating to these debt securities.

This section briefly summarizes the material provisions of the indenture and uses some terms that are not defined in this prospectus but that are defined in the indenture. This summary is not complete and we qualify it by reference to the indenture. The indenture is on file with the SEC, and we have incorporated it by reference in this prospectus. You should read the indenture for a complete understanding of its provisions and for the definition of some terms used in this summary. In this summary, we have included references to section numbers of the indenture so that you can easily locate these provisions.

The debt securities that we may issue under this indenture will be unsecured obligations of IDACORP, Inc. exclusively, and not the obligations of any of our subsidiaries. The indenture does not limit the amount of debt securities that we may issue and it does not restrict the amount or type of other debt that we or our subsidiaries may issue or contain any other provisions that would afford holders of the debt securities protection in the event of a highly leveraged transaction. We may use other indentures or documentation containing provisions different from those included in the indenture under which we are offering these debt securities in connection with future issues of debt securities.

We are a holding company whose primary source of funds is cash received from our subsidiaries in the form of dividends or other intercompany transfers. For a more detailed description of the dividend restrictions applicable to our subsidiaries, see “About IDACORP—Dividends from Subsidiaries” above. If any of our subsidiaries liquidate or reorganize, the claims of the subsidiary’s creditors to the proceeds will be prior to the claims of our creditors, except to the extent we are a creditor of the subsidiaries. As a result of these factors, the debt securities will be effectively subordinated to all existing and future claims of creditors of Idaho Power Company and other subsidiaries, including trade creditors, debt holders, secured creditors, taxing authorities and guarantee holders.

The indenture does not limit the amount of debt securities that we may issue, nor does it limit us or our subsidiaries from issuing any other unsecured debt. The debt securities that we are offering in this prospectus will rank equal in right of payment to our other unsecured indebtedness that is outstanding now or that we may issue in the future, except for any indebtedness that, by its terms, is subordinate to these debt securities. Although our subsidiaries are parties to agreements that limit the amount of additional indebtedness they may incur, they retain the ability to incur substantial additional indebtedness and other liabilities.

We will issue debt securities in series. Each series of debt securities may have different terms and, in some cases, debt securities of the same series may have different terms. We need not issue all debt securities of one series at the same time and, unless otherwise provided, we may reopen a series, without the consent of the holders of the debt securities of that series for issuances of additional debt securities of that series. One or more series of the debt securities may be issued with the same or various maturities at par, above par or at a discount.

Terms of the Debt Securities

Each prospectus supplement will describe the terms of a series of debt securities, including:

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the title of the series,

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any limit on the aggregate principal amount of the series,

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the date or dates on which we will issue the debt securities of that series and on which we will pay the principal amount and any premium,

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the rate or rates at which the debt securities of that series will bear interest, or how we will determine the rate or rates,

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the date or dates from which interest will accrue,

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the dates on which we will pay interest on the debt securities of that series and the regular record dates for the interest payment dates,

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the place or places where we will pay the principal of, premium, if any, and interest, if different from those we describe in this prospectus,

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any redemption terms, including mandatory redemption through a sinking fund or otherwise, redemption at our option and redemption at the option of the holder,

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whether any debt securities of that series will be issued as original discount securities and the amount of the discount,

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any events of default, interest rates payable upon an event of default, or restrictive covenants if other than set forth in this prospectus,

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the denominations in which we will issue the debt securities of that series, if other than denominations of $1,000 and any integral multiple of $1,000,

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the provisions for the satisfaction and discharge of the indenture if different from those we describe in this prospectus, and

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any other terms of the debt securities of the series which are not inconsistent with the provisions of the applicable indenture.

Form and Exchange

Unless we state otherwise in the prospectus supplement:

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we will issue the debt securities in fully registered form, without coupons, in denominations of $1,000 or in any larger amount equally divisible by $1,000,

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a holder of debt securities may exchange debt securities, without charge, for an equal aggregate principal amount of debt securities of the same series, having the same issue date and with identical terms and provisions, and

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a holder of debt securities may transfer debt securities, without charge, other than applicable stamp taxes or other governmental charges. Indenture, Sections 3.2 and 3.6

Unless we state otherwise in the prospectus supplement, the transfer of debt securities may be registered and exchanged at the corporate trust office of the trustee in New York, New York, as security registrar. We may change the place and designate one or more additional places for registration of transfer and exchange but we are required to maintain an office or agency in New York, New York for that purpose. Indenture, Section 4.2

We are not required to execute or to provide for the registration of transfer or exchange of any debt security:

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during a period of 15 days prior to giving any notice of redemption with respect to that debt security, or

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that has been selected for redemption in whole or in part, except the unredeemed portion of any debt security being redeemed in part. Indenture, Section 3.6

We may issue all or some of the debt securities in book-entry form, which means that global notes, not certificates, will represent the debt securities. If we issue global notes representing any debt securities, then a

depository that we select will keep a record of the beneficial interests in the global notes and record any transfers of beneficial interests. The global notes will be registered in the name of the depository and the depository will be considered the sole owner of the debt securities represented by the global notes for all purposes of the indenture. Indenture, Section 3.1

See “Book-Entry System” for a description of additional requirements as to the form and method of exchange of the debt securities. We will describe any additional requirements as to the form and method of exchange of debt securities in the prospectus supplement. Indenture, Sections 2.4 and 3.1

Payment and Paying Agent

Unless we state otherwise in the prospectus supplement, we will pay interest on each debt security to the person in whose name the debt security is registered as of the close of business on the regular record date for that interest payment date. If we have defaulted in the payment of interest on any debt security, we may pay the defaulted interest to the holder of the debt security as of the close of business on a special record date that is not less than 10 days prior to the date we propose to pay the defaulted interest. Notice of the special record date will be given by mail at least 15 days before the special record date. We may also pay defaulted interest in any other lawful manner permitted by requirements of any securities exchange on which the debt security may be listed, if the trustee deems that manner of payment practicable. Indenture, Section 3.8

Unless we state otherwise in the prospectus supplement, we will pay the principal of and premium, if any, and interest at maturity at the corporate trust office of the trustee in New York, New York, as our paying agent. We may change the place of payment. We may appoint one or more additional paying agents and may remove any paying agent, all at our discretion. Indenture, Section 4.2

If we deposit money with the paying agent to pay any amounts due on the debt securities and the holder does not claim the money within two years, the paying agent will return the money to us and we will be responsible for paying the holder. Indenture, Section 12.5

Events of Default

Except to the extent modified or deleted in a supplemental indenture or applicable resolution of the board of directors under which a series of debt securities is issued and described in the applicable prospectus supplement, each of the following will be an Event of Default with respect to each series of debt securities issued under the indentures:

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failure to pay the principal of, or premium, if any, on, any debt security of that series when due and payable at maturity and upon redemption, and the time for payment has not been extended or deferred,

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failure to pay interest on any debt security of that series when due and our failure continues for 30 days, and the time for payment has not been extended or deferred,

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failure to make a sinking fund payment when due with respect to debt securities of that series,

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failure to observe or perform any other covenant, warranty or agreement contained in the debt securities of that series or in the indenture, except for a covenant, agreement or warranty included in the indenture solely for the benefit of another series of debt securities, and our failure continues for 60 days after we have received written notice from the trustee or holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series,

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events relating to our bankruptcy, insolvency or reorganization, and

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any other event of default with respect to debt securities of that series specified in the applicable prospectus supplement. Indenture, Section 6.1

An event of default with respect to the debt securities of any series does not necessarily constitute an event of default with respect to any other series of debt securities issued under the indenture. Unless we cure the default,

the trustee is required to notify you of any default known to it within 90 days after the default has occurred. Except in the case of a payment default, the trustee may withhold notice if it considers such withholding to be in the interest of the holders. Indenture, Sections 6.1 and 6.11

If an event of default with respect to debt securities of any series, other than due to events of bankruptcy, insolvency or reorganization, occurs and is continuing, the trustee or the holders of at least 25% in aggregate principal amount of the outstanding debt securities of that series or, in the case of certain defaults that affect all series then outstanding, the holders of at least 25% in aggregate principal amount of all debt securities outstanding acting as a single class, by notice in writing to us, and to the trustee if given by the holders, may declare the unpaid principal of and accrued interest to the date of acceleration on all the outstanding debt securities of that series to be due and payable immediately. The holders of a majority of the principal amount of the outstanding debt securities of that series or, in the case of certain defaults that affect all series then outstanding, the holders of a majority in aggregate principal amount of all debt securities outstanding acting as a single class, upon the conditions provided in the indenture, including the requirement that we have paid all the principal and interest that has become due on that series other than by reason of acceleration, may rescind an acceleration and its consequences with respect to that series. Indenture, Section 6.1

If an event of default occurs due to bankruptcy, insolvency or reorganization, all unpaid principal of and accrued interest on the outstanding debt securities of all series will become immediately due and payable without any declaration or other act on the part of the trustee or any holder. Indenture, Section 6.1

The holders of a majority in principal amount of the outstanding debt securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the trustee, or exercising any trust or power conferred on the trustee, with respect to the debt securities of that series. Indenture, Section 6.9

Subject to the provisions of the indenture relating to the duties of the trustee, if an event of default shall occur and be continuing, the trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request or direction of any of the holders, unless the holders have offered to the trustee reasonable indemnity. Indenture, Section 7.2

The indenture provides that we must periodically file statements with the trustee regarding compliance by us with all conditions and covenants contained in the indenture. Indenture, Section 4.6

Redemption

We will describe any terms for the optional or mandatory redemption of a particular series of debt securities in the applicable prospectus supplement. In order to exercise our right to redeem a debt security, we must give the holder notice by mail at least 30 days prior to the date fixed for redemption.

If we want to redeem fewer than all the debt securities of a series, the trustee will choose the particular debt securities to be redeemed by lot or by another method described in the applicable prospectus supplement. Indenture, Article Fourteen

Consolidation, Merger or Sale

The indenture provides that we will not consolidate with, or merge into, or sell all or substantially all of our assets to, any person, unless:

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the successor corporation, if we are not the survivor, expressly assumes in writing all of our obligations under the outstanding debt securities and the indenture,

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immediately before and after giving effect to the transaction, no event of default shall have occurred and be continuing, and

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we deliver to the trustee an officer’s certificate and an opinion of counsel stating that the transaction and the supplemental indenture comply with the indenture. Indenture, Article Eleven

Modification of Indenture

We may modify the indenture, without notice to or the consent of any holders of debt securities, with respect to certain matters that do not materially adversely affect the holders of any debt securities. Indenture, Section 10.1

In addition, we may modify certain of our rights and obligations and the rights of holders of the debt securities with the consent of the holders of not less than a majority in aggregate principal amount of the outstanding debt securities affected by the modification, voting as one class. Indenture, Section 10.2

Without the consent of each holder of any outstanding debt security affected, no amendment or modification may:

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change the stated maturity of any debt security,

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reduce the principal amount of or the amount of any premium on, or reduce the rate of interest on, or extend the time for payment or change the method of calculating interest on, any debt security, or extend the time for payment of those amounts, reduce the amount payable on redemption, or reduce the amount of principal of an original issue discount security that would be due and payable upon acceleration of maturity,

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impair the right to institute suit for the enforcement of any payment with respect to any debt security,

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reduce the percentage in principal amount of outstanding debt securities of any series necessary to modify or amend the indenture, or to waive compliance with provisions of the indenture or defaults or events of default and their consequences, or

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subordinate any debt securities to any other of our indebtedness. Indenture, Section 10.2

Waiver of Defaults

The holders of not less than a majority in aggregate principal amount of the outstanding debt securities of any series may waive any default or event of default with respect to that series, except if certain defaults relate to all series of outstanding debt securities, the holders of not less than a majority in aggregate principal amount of all outstanding debt securities voting as one class may waive the default. Payment and bankruptcy defaults and defaults with respect to a provision that cannot be modified or amended without the consent of the holder of each debt security affected may not be waived in this manner. Indenture, Section 6.10

Defeasance

Unless we state otherwise in the prospectus supplement relating to the debt securities of a particular series, the indenture provides that we shall be discharged from our obligations under the indenture with respect to any series of debt securities at any time prior to the maturity date or redemption of that series when

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we have irrevocably deposited in trust with the trustee:

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sufficient funds to pay the principal of and premium, if any, and interest to the maturity date or redemption of, the debt securities of that series, or

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an amount of direct obligations of, or obligations guaranteed by, the United States government as will be sufficient to pay when due the principal of, and premium, if any, and interest to the maturity date or redemption of, the debt securities of that series, and

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we have paid all other sums payable with respect to the debt securities of that series. Upon the discharge of the indenture with respect to a particular series, the holders of debt securities of that series shall no longer be entitled to the benefits of the indenture, except for purposes of registration of transfer, exchange and replacement of lost, stolen or mutilated debt securities. Indenture, Section 12.1 and 12.3

Concerning the Trustee

We and our affiliates may conduct banking transactions with the trustee or its affiliates in the normal course of business.

Governing Law

The indenture and the debt securities will be governed by and construed under the laws of the state of Idaho, except that the obligations, rights and remedies of the trustee will be determined under the laws of the state of New York.

BOOK-ENTRY SYSTEM

We may issue all or some of the debt securities in book-entry form, which means that global notes, not certificates, will represent the securities. If we issue global notes representing any securities, the following provisions will apply to all book-entry securities:

Unless otherwise indicated in the applicable prospectus supplement, the Depository Trust Company, New York, NY, which we refer to as “DTC,” will act as securities depository for the securities. We will issue the securities as fully-registered securities registered in the name of Cede & Co. or such other name as may be requested by an authorized representative of DTC. We will issue one or more fully-registered security certificates for each issue of the securities, in the aggregate principal amount of the issue, and we will deposit the certificates with the trustee to hold as agent for DTC. We and the trustee will treat Cede & Co. as the holder of the securities for all purposes.

DTC has informed us that it is a limited-purpose trust company organized under the New York Banking Law, a “banking organization” within the meaning of the New York Banking Law, a member of the Federal Reserve System, a “clearing corporation” within the meaning of the New York Uniform Commercial Code, and a “clearing agency” registered pursuant to the provisions of Section 17A of the Exchange Act. DTC also facilitates the post-trade settlement among direct participants of sales and other securities transactions in deposited securities through electronic computerized book-entry transfers and pledges between direct participants’ accounts. This eliminates the need for physical movement of securities certificates. Direct participants include both U.S. and non-U.S. securities brokers and dealers, banks, trust companies, clearing corporations, and certain other organizations. DTC is a wholly-owned subsidiary of The Depository Trust & Clearing Corporation, or “DTCC”. DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies. DTCC is owned by the users of its regulated subsidiaries. Access to the DTC system is also available to others such as both U.S. and non-U.S. securities brokers and dealers, banks, trust companies and clearing corporations that clear through or maintain a custodial relationship with a direct participant, either directly or indirectly. The DTC rules applicable to its participants are on file with the SEC. More information about DTC can be found at www.dtcc.com and www.dtc.org.

Purchases of securities under the DTC system must be made by or through direct participants, which will receive a credit for the securities on DTC’s records. The ownership interest of each actual purchaser, the beneficial owner, is in turn to be recorded on the direct and indirect participants’ records. Beneficial owners will not receive written confirmation from DTC of their purchase. Beneficial owners are, however, expected to receive written confirmations providing details of the transaction, as well as periodic statements of their holdings, from the direct or indirect participant through which the beneficial owner entered into the transaction. Transfers of ownership interests in the securities are to be accomplished by entries made on the books of direct and indirect participants acting on behalf of beneficial owners. Beneficial owners will not receive certificates representing their ownership interests in the securities, except in the event that use of the book-entry system for the securities is discontinued.

To facilitate subsequent transfers, all securities deposited by direct participants with DTC are registered in the name of DTC’s partnership nominee, Cede & Co., or such other name as may be requested by an authorized representative of DTC. The deposit of securities with DTC and their registration in the name of Cede & Co. or such other DTC nominee do not effect any change in beneficial ownership. DTC has no knowledge of the actual beneficial owners of the securities. DTC’s records reflect only the identity of the direct participants to whose accounts the securities are credited, which may or may not be the beneficial owners. The direct and indirect participants will remain responsible for keeping account of their holdings on behalf of their customers.

Conveyance of notices and other communications by DTC to direct participants, by direct participants to indirect participants, and by direct participants and indirect participants to beneficial owners will be governed by arrangements among them, subject to any statutory or regulatory requirements that may be in effect from time to time.

Redemption notices will be sent to DTC. If less than all of the securities within an issue are being redeemed, DTC’s practice is to determine by lot the amount of the interest of each direct participant in the issue to be redeemed.

Neither DTC nor Cede & Co. (nor any other DTC nominee) will consent or vote with respect to the securities unless authorized by a direct participant in accordance with DTC’s money market instrument procedures. Under its usual procedures, DTC mails an omnibus proxy to the issuer as soon as possible after the record date. The omnibus proxy assigns Cede & Co.’s consenting or voting rights to those direct participants to whose accounts the securities are credited on the record date, identified in a listing attached to the omnibus proxy.

Redemption proceeds and distributions, including principal and interest payments, on the securities will be made to Cede & Co., or such other nominee as may be requested by an authorized representative of DTC. DTC’s practice is to credit direct participants’ accounts upon DTC’s receipt of funds and corresponding detail information from us or our agent on the payable date in accordance with their respective holdings shown on DTC’s records. Payments by participants to beneficial owners will be governed by standing instructions and customary practices as is the case with securities held for the accounts of customers in bearer form or registered in street name. Payment by participants to beneficial owners will be the responsibility of the participants and not of DTC, any agents or us, subject to any statutory or regulatory requirements as may be in effect from time to time. Payment of redemption proceeds and distributions to Cede & Co. (or such other nominee as may be requested by an authorized representative of DTC) is our responsibility or the responsibility of our paying agents. Disbursement of such payments to direct participants will be the responsibility of DTC, and disbursement of such payments to the beneficial owners will be the responsibility of direct and indirect participants.

In case of any optional tender for or mandatory purchase of securities, pursuant to their terms, a beneficial owner shall give notice to elect to have its securities purchased or tendered through its participant to the tender/remarketing agent and shall effect delivery of the securities by causing the direct participant to transfer the participant’s interest in the securities, on DTC’s records, to the tender/remarketing agent. The requirement for physical delivery of securities in connection with an optional tender or a mandatory purchase will be deemed satisfied when the ownership rights in the securities are transferred by direct participants on DTC’s records and followed by a book-entry credit of tendered securities to the tender/remarketing agent’s DTC account.

DTC may discontinue providing its services as depository with respect to the securities at any time by giving reasonable notice to us or to our agent. Under such circumstances, in the event that a successor depository is not obtained, security certificates are required to be printed and delivered.

We may decide to discontinue use of the system of book-entry-only transfers through DTC (or a successor securities depository). In that event, security certificates will be printed and delivered to DTC.

Neither we, the trustee, any paying agent, nor the registrar for the securities will have any responsibility or liability for any aspect of the records relating to or payments made on account of beneficial ownership interests in a global security or for maintaining, supervising or reviewing any records relating to these beneficial ownership interests.

The information in this section concerning DTC and DTC’s book-entry system has been obtained from sources that we believe to be reliable, but we take no responsibility for the accuracy thereof.

The underwriters, dealers or agents of any of the securities may be direct participants of DTC.

USE OF PROCEEDS

Unless we state otherwise in the prospectus supplement, we will add the net proceeds from the sale of the securities to our general funds. We may use our general funds for any of the following purposes:

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to invest in, or make loans to, our subsidiaries,

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to repay indebtedness,

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to pay for acquisitions, or

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other general corporate purposes.

The precise amount and timing of the application of such proceeds will depend on our funding requirements, market conditions and the availability and cost of other funds. If we do not use the proceeds immediately, we may temporarily invest them in short-term instruments.

PLAN OF DISTRIBUTION

Methods of Offer and Sale

We may sell the securities offered by this prospectus:

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through underwriters or dealers,

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through agents,

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directly to one or more purchasers, or

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through a combination of any of the above methods of sale.

Through Underwriters or Dealers. If we use underwriters in the sale, the underwriters will buy the securities for their own account. The underwriters may resell the securities in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of the sale. The underwriters may sell the securities directly or through underwriting syndicates that managing underwriters represent. Unless we state otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions, and the underwriters will be obligated to purchase all of the securities if they purchase any of them. If we use a dealer in the sale, we will sell those securities to the dealer as principal. The dealer may then resell the securities to the public at varying prices determined at the time of resale. Any initial public offering price and any discounts or concessions allowed or reallowed or paid to dealers may be changed from time to time.

Through Agents. We may from time to time designate one or more agents to sell the securities. Unless we state otherwise in the prospectus supplement, any agent will agree to use its best efforts to solicit purchases for the period of its appointment.

Directly. We may sell the securities directly to one or more purchasers. In this case, there will be no underwriters or agents.

General Information

Our common stock is listed on the New York Stock Exchange under the symbol “IDA.” The debt securities may or may not be listed on a national securities exchange. You should read the applicable prospectus supplement for a discussion of this matter.

The prospectus supplement will state:

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the names of any underwriters, dealers or agents, and the amounts of securities underwritten, purchased or sold by each of them,

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the terms of the securities offered,

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the purchase price of the securities and the proceeds we will receive from the sale,

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any initial public offering price,

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any discounts or commissions and other items constituting underwriters’ or agents’ compensation, and

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any discounts or concessions allowed or reallowed or paid to dealers.

We may authorize agents, underwriters or dealers to solicit offers from certain institutions. We may sell the securities to these institutions for delayed delivery at a specified date in the future. At that time, they will pay the public offering price on the terms we describe in the prospectus supplement.

We may distribute the securities from time to time in one or more transactions at:

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a fixed price or prices, which may be changed,

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market prices prevailing at the time of sale,

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prices related to such prevailing market prices, or

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negotiated prices.

We may also engage in at-the-market offerings of our common stock in an existing trading market. Any at-the-market offering will be through an underwriter or underwriters acting as principal or through an agent or agents for us.

Underwriters, agents, dealers and remarketing firms may be entitled under agreements entered into with us to indemnification by us against civil liabilities, including liabilities under the Securities Act of 1933, or to contribution by us with respect to payments which the underwriters or agents may be required to make in respect thereof. Underwriters, agents, dealers and remarketing firms may be customers of, engage in transactions with, or perform services for us and our subsidiaries and affiliates in the ordinary course of business.

INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

The SEC allows us to incorporate by reference information into this prospectus, which means that we can disclose important information to you by referring you to other documents filed separately with the SEC. The information incorporated by reference is considered to be part of this prospectus. We incorporate by reference the following documents that we filed with the SEC (SEC file number 1-14465):

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Annual Report on Form 10-K for the year ended December 31, 2024, filed on February 20, 2025,

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Current Reports on Form 8-K filed on January 2, 2025, and February 13, 2025, and

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Description of our common stock contained in Exhibit 4.10 of our Annual Report on Form 10-K for the year ended December 31, 2023, and any amendment or report filed for the purpose of updating such description.

We also incorporate by reference all documents we subsequently file pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date of this prospectus and before we terminate the offering. We are not incorporating by reference any documents or portions of documents that are not deemed “filed” with the SEC, including any information furnished pursuant to Items 2.02 or 7.01 of Form 8-K.

Any statement contained in a document incorporated or deemed to be incorporated by reference or deemed to be part of the prospectus shall be deemed to be modified or superseded for purposes of the prospectus to the extent that a statement contained in the prospectus or in any other subsequently filed document which also is or is deemed to be incorporated by reference or deemed to be part of the prospectus modifies or replaces such statement. Any statement so modified or superseded shall not be deemed to constitute part of the prospectus for purposes of the Securities Act.

We will provide to each person, including any beneficial owner, upon request, to whom this prospectus is delivered, a copy of any or all of the information that has been incorporated by reference in this prospectus but not delivered with this prospectus. You may obtain a copy of this information at no cost, by written or oral request to us at the following address:

Shareowner Services

IDACORP, Inc.

1221 West Idaho Street

Boise, ID 83702

Telephone 208-388-2200

You may also access these documents at our website at www.idacorpinc.com.

We take responsibility only for information contained or incorporated by reference in this prospectus, the applicable prospectus supplement, and the applicable pricing supplement, if any. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. We are not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted.

You should assume that the information appearing in this prospectus is accurate as of the date of this prospectus only. Our business, financial condition and results of operations may have changed since that date.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the SEC. The SEC maintains an internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC. The address of that site is www.sec.gov. Information about us is also available at our website at www.idacorpinc.com. However, the information on our website is not a part of this prospectus.

This prospectus is part of a registration statement on Form S-3 that we filed with the SEC relating to the securities covered by this prospectus. This prospectus does not contain all the information included in the registration statement. You may review a copy of the registration statement on the SEC’s internet site referred to above.

LEGAL MATTERS

Unless otherwise indicated in the applicable prospectus supplement, Perkins Coie LLP, Seattle, Washington, and Julia A. Hilton, Vice President and General Counsel of IDACORP, Inc., will pass upon the validity of the securities and other legal matters for us. Unless otherwise indicated in the applicable prospectus supplement, Sullivan & Cromwell LLP, Los Angeles, California, will pass upon the validity of the securities for any underwriter, dealer or agent. Sullivan & Cromwell LLP or other counsel identified in an applicable prospectus supplement may, for matters governed by the laws of the state of Idaho, rely upon the opinion of Perkins Coie LLP and Ms. Hilton or such other counsel identified in the applicable prospectus supplement. Ms. Hilton owns shares of vested and unvested restricted common stock of IDACORP, Inc. acquired pursuant to employee benefit plans and participates in various employee benefit plans offered to employees of IDACORP, Inc. and Idaho Power Company.

EXPERTS

The financial statements of IDACORP, Inc. incorporated by reference in this prospectus, and the effectiveness of IDACORP, Inc.’s internal control over financial reporting have been audited by Deloitte & Touche LLP, an independent registered public accounting firm, as stated in their reports. Such financial statements are incorporated by reference in reliance upon the reports of such firm, given their authority as experts in accounting and auditing.

Up to $600,000,000

LOGO

IDACORP, Inc.

Common Stock

PROSPECTUS SUPPLEMENT

May 15, 2026

BofA Securities

BTIG

J.P. Morgan

Mizuho

Morgan Stanley

MUFG

Wells Fargo Securities