Quantisnow Insider Buying Index

Insider buying in May 2025

Last updated . Recomputed daily.

In May 2025, insiders bought $1.30B of stock in open-market purchases across 568 companies, up 3.1% from April, against $25.42B of open-market sales, based on 1,299 Form 4 purchase filings.

Source: Quantisnow, Quantisnow Insider Buying Index, May 2025

Key figures

Insider purchase value
$1.30B
Prior month: $1.26B
Insider purchase filings
1,299
Prior month: 752
Companies with insider buying
568
Prior month: 310
Cluster buys (3+ filings)
162
Prior month: 93
Insider open-market sale value
$25.42B
Prior month: $2.75B
Buy-to-sell value ratio
0.05
Prior month: 0.46
All Form 4 filings
18,510
Prior month: 11,865

Companies with the largest insider purchases, May 2025

Methodology

An insider purchase is a Form 4 filed with the SEC whose non-derivative table reports an open-market purchase (transaction code P) by an officer, director or 10% owner. Quantisnow parses every Form 4 from EDGAR as it is accepted, computes the dollar value of each transaction (shares times reported price), and tags filings with a purchase as the Insider Buy category.

Purchase value sums those reported dollar values across all purchase filings in the month. Sale value does the same for open-market sales (transaction code S) on every other Form 4, so tax withholding, option exercises, grants and gifts are excluded from both sides. Transactions reported without a price carry no dollar value. Amended Form 4s (4/A) are excluded because they restate a filing already counted, and transactions priced above $10,000 per share or worth more than $2 billion are excluded as reporting errors (typically a price filed in cents or a foreign currency). A filing whose purchases exceed twice the company's current market capitalization is also excluded from value (usually an issuer reporting its own share issuance).

Companies counts distinct issuers with at least one purchase filing. A cluster buy is an issuer with three or more purchase filings in the same month, a common proxy for several insiders buying together.

Figures are recomputed daily from the Quantisnow event database. The current month is marked as month to date until it closes; the previous month is recomputed daily through the following month to pick up late filings, then stays fixed.

April 2026: Insider purchase tagging was interrupted for part of this month, so purchase counts and values are incomplete. Form 4 totals are unaffected.

October 2026: Insider purchase tagging was interrupted for part of this month, so purchase counts and values are incomplete. Form 4 totals are unaffected.

Definitions for every column are in the JSON download.

Metric definitions

Insider purchase value
(buyValue): Dollar value of open-market purchases (transaction code P) reported on Form 4.
Insider purchase filings
(buys): Form 4 filings reporting at least one open-market purchase.
Companies with insider buying
(companies)
Cluster buys (3+ filings)
(clusters): Companies with three or more insider purchase filings in the month.
Insider open-market sale value
(sellValue): Dollar value of open-market sales (transaction code S) reported on Form 4.
Buy-to-sell value ratio
(buySellRatio): Purchase value divided by open-market sale value.
All Form 4 filings
(form4)

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Free to reuse under CC BY 4.0 with attribution to Quantisnow and a link to this page.

Cite this dataset (APA)

Quantisnow. (2026). Quantisnow Insider Buying Index, May 2025 [Data set]. Retrieved October 27, 2026, from https://www.quantisnow.com/data/insider-buying/2025-05

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<figure style="margin:0;max-width:720px"><a href="https://www.quantisnow.com/data/insider-buying"><img src="https://www.quantisnow.com/data/insider-buying.svg" alt="Quantisnow Insider Buying Index chart" width="720" height="340" style="width:100%;height:auto" loading="lazy"></a><figcaption style="font:12px sans-serif;color:#5b6470">Source: <a href="https://www.quantisnow.com/data/insider-buying">Quantisnow Insider Buying Index</a> by Quantisnow</figcaption></figure>

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