8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

      Date of Report (Date of earliest event reported): September 14, 2026

     

CABALETTA BIO, INC.

(Exact name of Registrant as Specified in Its Charter)


Delaware	001-39103	82-1685768
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)

2929 Arch Street Suite 600
Philadelphia, Pennsylvania		19104
(Address of Principal Executive Offices)		(Zip Code)

      Registrant’s Telephone Number, Including Area Code: (267) 759-3100

     

      Not Applicable

     

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:


Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common Stock, par value $0.00001 per share	CABA	The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

In connection with Cabaletta Bio’s (the “Corporation”) June 2025 underwritten public offering, the Corporation issued 53,090,190 common stock warrants (the “Common Stock Warrants”) that had an exercise price of $2.50 per whole share of its common stock and an expiration date of September 12, 2026 (the “Expiration Date”).

From issuance through June 30, 2026, 5,275,100 Common Stock Warrants were exercised resulting in aggregate gross proceeds of approximately $13.2 million. From July 1, 2026 through the Expiration Date, 46,011,900 Common Stock Warrants were exercised resulting in aggregate gross proceeds of approximately $115.0 million. The aggregate gross proceeds from exercises of the Common Stock Warrants from issuance through the Expiration Date is approximately $128.2 million.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.


	CABALETTA BIO, INC.

Date: September 14, 2026	By:	/s/ Steven Nichtberger
		Steven Nichtberger
		Chief Executive Officer and President (Principal Executive Officer)