What is SEC Form 4?

SEC Form 4 is the U.S. Securities and Exchange Commission filing that corporate insiders - directors, officers, and beneficial owners of more than 10% of a company's stock - must submit to report changes in their ownership of the company's securities. It is required under Section 16(a) of the Securities Exchange Act of 1934, and since the 2002 Sarbanes-Oxley Act it must be filed electronically on EDGAR within two business days of the transaction.

Two SEC rulemakings did that work, and both are worth knowing if you care about how fast this data moves. The two-business-day deadline came from Release 34-46421, "Ownership Reports and Trading by Officers, Directors and Principal Security Holders" (August 2002), which replaced a monthly cycle under which a trade made on the 2nd of a month might not surface until the 10th of the next. Mandatory electronic filing and same-day EDGAR posting followed in Release 33-8230, "Mandated Electronic Filing and Web Site Posting for Forms 3, 4 and 5" (2003). Before those two changes, insider trading data was effectively a monthly paper archive; afterwards it became a real-time feed.

Because the deadline is so short, Form 4 is the fastest, most reliable public window into what the people who run a company are doing with their own money. InsiderAlpha ingests every Form 4 from SEC EDGAR in real time so you see these trades the moment they are filed.

Who has to file Form 4?

• Directors and named executive officers (CEO, CFO, COO, and other "Section 16 officers") of public companies.
• Beneficial owners of more than 10% of any class of a company's registered equity - often hedge funds, private-equity firms, and activist investors.
• Certain related parties - trusts, family members, and affiliated entities whose holdings are attributed to an insider.

How to read a Form 4

A Form 4 has two tables. Table I covers non-derivative securities (ordinary common stock). Table II covers derivative securities (options, warrants, convertible notes, RSUs). For each transaction the form reports:

• Transaction date - when the trade actually happened (not when it was filed).
• Transaction code - a one-letter code describing the nature of the trade (see below).
• Amount, price, and resulting shares owned - how many shares changed hands, at what price, and the insider's total stake afterward.
• Ownership type - "D" for direct ownership or "I" for indirect (e.g. held through a trust or LLC).

Common transaction codes

• P - Open-market or private purchase
• S - Open-market or private sale
• A - Grant or award (usually equity compensation)
• M - Exercise or conversion of a derivative security
• F - Shares withheld to pay taxes or an exercise price
• G - Bona-fide gift

Open-market purchases (code P) are widely considered the most informative signal because the insider is committing personal capital with direct knowledge of the business. Awards (A) and tax-withholding dispositions (F) are routine compensation events and carry far less information.

Direct vs. indirect, derivative vs. non-derivative

Two distinctions trip up first-time readers. Indirect holdings (code "I") are real economic exposure held through an intermediary - they count. And a Table II derivative exercise (code M) often pairs with a same-day sale (code S) of the underlying stock; that is a mechanical compensation transaction, not a conviction bet.

Why does it matter?

Academic research - notably Lakonishok & Lee (2001) and Cohen, Malloy & Pomorski (2012) - finds that routine insider selling contains little predictive information, but opportunistic insider buying, and especially clustered buying by several insiders at once, is associated with positive abnormal returns over the following months.

How fast do Form 4 filings actually arrive?

The legal deadline is two business days, and in practice most insiders file close to it. Across the 10,315 open-market purchase transactions filed with the SEC in 2026 through late July, the median gap between the trade date and the filing date in InsiderAlpha's data is 2.8 calendar days. Nine out of ten purchases are filed within 7 calendar days of the trade. Weekends explain why the calendar-day figures run a little above the two-business-day rule.

That lag matters if you trade on this data. The market reaction to insider buying concentrates in the first days after disclosure, so a purchase that is already a week old when you see it has lost much of its edge. This is why InsiderAlpha polls EDGAR continuously during filing hours and scores filing recency directly, instead of batching updates once a day.

Form 4 vs Form 3 and Form 5

Form 4 is one of three ownership reports required under Section 16(a):

• Form 3 is the initial statement of ownership, filed within 10 days of a person becoming a director, officer, or 10% owner. It reports holdings, not trades.
• Form 4 reports changes in ownership within two business days. This is the form where actual buys and sells appear.
• Form 5 is an annual catch-up, due within 45 days of the company's fiscal year end, covering small or exempt transactions (such as certain gifts) that did not require a Form 4 at the time.

Affiliates who intend to sell restricted or control stock also file Form 144, which is a notice of an intended sale rather than a report of a completed one. See Form 4 vs Form 144 for the full comparison.

Amendments and duplicate filings

Insiders sometimes correct a filing with a Form 4/A amendment, and the same transaction occasionally reaches EDGAR more than once through different filing agents. Left unhandled, those extra documents inflate any count of insider activity. InsiderAlpha groups each company-insider-date combination into a filing group, marks one filing as primary, and treats the rest as amendments or duplicates. Every count and signal on the platform is built from the deduplicated primary set.

Form 4 by the numbers

As of August 3, 2026, InsiderAlpha tracks 221,347 deduplicated Form 4 filings covering 6,114 companies and 53,567 distinct insiders. The live count is higher and moves daily; the figures here are the frozen snapshot our published studies were computed on. Over the trailing 12 months those filings recorded roughly 15,900 open-market purchase transactions worth about $39 billion, against roughly 74,000 sale transactions worth about $171 billion. Sales outnumber purchases by more than four to one.

That imbalance is normal, not alarming. Insiders receive most of their equity through compensation, so selling is their default behavior. It is also exactly why a genuine open-market purchase stands out: it is the rarer event, and the one that requires the insider to commit outside cash.

What a Form 4 does not tell you

A Form 4 reports what happened, not why. It does not disclose the insider's reasoning, their view on valuation, or whether they hold offsetting positions elsewhere. It cannot tell you whether a purchase will work out. Insider buying shifts the odds; it is not a guarantee. Treat Form 4 data as one input into a broader process, not a complete strategy.

Frequently asked questions

Where can I find Form 4 filings for free?

Every Form 4 is public on SEC EDGAR the moment it is accepted, at no cost and with no account. EDGAR is free but raw: filings arrive as XML documents, amendments sit next to originals, and there is no screening or scoring. InsiderAlpha parses, deduplicates, and scores the same public data in real time.

Do all insider trades appear on Form 4?

All reportable changes in beneficial ownership by Section 16 insiders do, with narrow exemptions that flow to the annual Form 5 instead. Trades by employees below the Section 16 officer level are not reported at all.

What happens if an insider files late?

Late Section 16 filings must be disclosed in the company's proxy statement, and the SEC does enforce the deadline. In September 2014 it charged 28 officers, directors and large shareholders, plus six companies, in a single sweep aimed at repeat late filers found with ranking algorithms over its own filing data. Some of those filings were late by years; 33 of the 34 settled, paying $2.6 million in penalties between them. In our 2026 purchase data the large majority of filings arrive within a week of the trade.

Where does the 10b5-1 checkbox come from?

From Release 33-11138, "Insider Trading Arrangements and Related Disclosures" (December 2022), which added the checkbox, imposed cooling-off periods before a new plan may trade, and required companies to file their insider trading policies as an exhibit to the annual report. The checkbox is the single most useful field on the form for separating a decision from a schedule, and it did not exist before 2023.

How InsiderAlpha helps

InsiderAlpha deduplicates Form 4 amendments, classifies every transaction, flags Rule 10b5-1 plan trades, and scores the high-conviction signals - large open-market officer buys and cluster buying - into a daily plan.

Browse the latest Form 4 filings → · Read a Form 4 box by box → · How to read insider buying signals →

This article is informational and is not investment advice.