Form 144 vs Form 4: What Each Filing Actually Tells You

Two different SEC filings carry information about insider sales, and most retail investors only watch one of them. Form 4 reports a transaction that has already happened — the share count moved, the cash exchanged hands, the position is now smaller. Form 144, by contrast, is a notice of intent to sell filed by affiliates of the issuer before the trade settles. Both filings are public on SEC EDGAR; both are easy to look up; and the gap between them tells you something neither filing tells you in isolation. This guide walks through what each form is, what it isn't, and how to read them together without overinterpreting either one.

What Form 144 Actually Is

Form 144 is required under Rule 144 of the Securities Act of 1933. The rule governs how "affiliates" of a public company — typically officers, directors, and 10% beneficial owners — can resell restricted or control securities into the public market. The mechanics are deliberately friction-laden: an affiliate who plans to sell more than 5,000 shares or more than $50,000 worth of stock in any three-month rolling window must file Form 144 with the SEC, and that filing must be made at the time the sale order is placed with a broker, not after settlement.

Three things follow from that timing rule that are easy to miss:

• Form 144 is forward-looking — it states a planned, not a completed, sale. The actual transaction may or may not happen as filed. The affiliate has 90 days from the filing date to complete the sale; if they don't, they can refile a fresh Form 144 or simply allow the disclosure to expire.
• Form 144 covers a window, not a single trade — the filing discloses an aggregate amount of shares an affiliate intends to sell, typically over the following quarter. The actual Form 4s that follow may show many smaller transactions adding up to (or short of) the planned amount.
• Form 144 explicitly cites the seller's 10b5-1 plan, if any — the form has a checkbox for "Plan or Contract" sales, and the affiliate must list the plan adoption date. This is one of the cleanest places to verify whether a Form 4 sale that comes later was pre-scheduled, rather than relying on inferred patterns.

What Form 4 Actually Is

Form 4 is the post-trade disclosure. It is required under Section 16(a) of the Securities Exchange Act of 1934 and must be filed within two business days of the transaction (this was tightened from the prior 10-day window in 2002 under Sarbanes-Oxley). Form 4 reports the actual share count transacted, the price per share, the transaction code (S for sale, P for purchase, M for option exercise, F for tax withholding, etc.), and the holder's resulting beneficial ownership in two tables — Table I for non-derivative securities and Table II for derivatives.

Three things to know about Form 4 that retail-investor coverage routinely gets wrong:

• "Beneficial ownership" includes more than direct holdings — Table II frequently carries the bulk of a founder's economic interest in dual-class companies. A Form 4 Table I balance of 36,000 shares on a founder's filing does not mean the founder owns 36,000 shares; the Table II derivative holdings (Class B convertibles, options, warrants) may carry many millions more. Reading multi-class Form 4 filings covers this trap in depth.
• The transaction code matters more than the dollar value — a $50M Form 4 with code "F" (tax withholding on RSU vesting) is fundamentally different from a $50M Form 4 with code "S" (open-market sale, no 10b5-1 footnote). One is forced; the other is discretionary. See Form 4 transaction codes explained for the full taxonomy.
• A 10b5-1 plan footnote on Form 4 turns the filing into compliance plumbing — pre-scheduled plan sales are explicitly not signal in the traditional sense. How to read 10b5-1 plan sales walks through that distinction.

The Useful Read: Comparing the Two

The clean signal that Form 144 and Form 4 produce together — but neither produces alone — is the gap between planned and executed selling. Three patterns to watch for:

Pattern 1: Form 144 Filed, Form 4 Follows in Full

The affiliate filed Form 144 in week 1, and across the following 90 days, the cumulative Form 4 share count matches the Form 144 planned amount. This is the textbook "10b5-1 plan executes as advertised" pattern. It is the dominant case at most large-cap companies, and it carries no incremental information beyond what the Form 144 already disclosed. Treat it as the noise floor.

Pattern 2: Form 144 Filed, Form 4 Follows Short

The affiliate filed Form 144 disclosing intent to sell, say, 100,000 shares. Across the 90-day window, Form 4 filings show only 60,000 shares actually sold. The remaining 40,000 shares of the plan went unfilled — either because price triggers didn't fire (in a discretionary plan with limit prices), the plan terminated early (10b5-1 plans can be canceled with appropriate disclosure), or the affiliate simply chose not to extend the sale across the full window. This pattern is mildly informative: it shows where the affiliate's price-of-indifference sits. Plans that consistently underfill imply the affiliate is content not to monetize at current price levels.

Pattern 3: Form 4 Filed Without Prior Form 144

This is the pattern with the most information density. An affiliate sells shares — disclosed via Form 4 — without having filed a Form 144 in advance. Three possible explanations:

• The sale was below the Form 144 reporting threshold (under 5,000 shares and under $50,000 across the trailing three months). Most CEO transactions exceed this; many director awards do not.
• The sale was not by an "affiliate" (e.g., a former officer who has been out of the role long enough to lose affiliate status). This is rare for currently-active Form 4 filers.
• The sale fits within an existing Rule 144(b)(1) safe harbor for non-affiliates — most common when a 10% holder steps below the 10% threshold and is no longer an affiliate at the time of sale.

The interesting cases are when none of the three explanations holds and the affiliate appears to have sold material shares without the advance notice. This is sometimes a compliance miss; more often it implies an undisclosed sale structure (e.g., a derivative-based exit, a forward-sale contract, or a private placement).

A Worked Example: Reading the Two Together

Consider a hypothetical Form 4 filing showing a CEO selling 250,000 shares at an average price of $80, across five trading days, with no 10b5-1 footnote on the filing itself. Form 4 alone reads as a discretionary sale. Now pull the EDGAR Form 144 archive for the same filer and look at the prior 30 days. If a Form 144 exists disclosing 250,000 shares "under a plan or contract" with a plan adoption date of nine months earlier, the Form 4 you were about to interpret as discretionary is actually a pre-scheduled 10b5-1 fill. The "discretionary" framing flips to plan-driven; the directional signal disappears.

For a non-hypothetical case, browse any large-cap CEO Form 4 stream alongside the same insider's Form 144 archive. Eric Yuan's Form 4 history against his Form 144 filings is a clean example: the Form 144 cadence implies a quarterly plan refresh, and the Form 4 execution typically matches the planned amount with high fidelity. Compare against George Kurtz's Form 4 history for a case where the Form 4 cadence is so regular that the 10b5-1 plan can be inferred without even pulling the Form 144.

Where to Find Both Filings

The cleanest source for either form is SEC EDGAR directly. Search by company CIK (for Form 4s the filings appear under the issuer's CIK; for Form 144s they appear under the affiliate's CIK or via the issuer's full-text search). The SEC's Form 144 search page lets you query by issuer name. 13F Insight pulls Form 4 data into structured insider profile pages — see the Mark Zuckerberg insider profile or browse the insider tape feed for current Form 4 activity across the platform.

Three Quick Reads for Practice

• Cross-check Form 144 against Form 4 share count over a 90-day window — the difference is the plan underfill, if any.
• Read the 10b5-1 checkbox on Form 144 — this is the cleanest way to confirm pre-scheduling without inferring from Form 4 cadence alone.
• Treat a Form 4 without a prior Form 144 as the rare event worth investigating — most Form 4s at affiliate-grade filers have a corresponding Form 144. When they don't, ask why.

Both filings are public, both are free, and both are searchable. The discipline of reading them together — not either one alone — is what separates structured insider-tape analysis from the kind of "CEO dumps stock" framing that reliably generates more heat than light.