What is an SEC Form 4?
By Outfox Editorial · Reviewed September 2, 2026
Quick answer
Form 4 is a public SEC filing used to report many changes in ownership by a public company’s directors, officers, and shareholders who own more than 10% of a registered class of its equity securities. It is usually due within two business days of the transaction.
Key takeaways
- Form 4 can reveal relatively recent activity by people closely connected to a company.
- Transaction code P generally identifies an open-market or private purchase; S generally identifies a sale.
- Awards, option exercises, gifts, and tax-withholding transactions should not be treated as ordinary purchases or sales.
- The original filing and its footnotes matter more than a headline about the filing.
What appears in the filing?
A Form 4 identifies the reporting person, the issuer, the reporting person’s relationship to the issuer, the transaction date, the security, the number of shares, the reported price, the transaction code, and the ownership remaining after the transaction. It can also include derivative securities and explanatory footnotes.
Outfox will preserve the accession number and official SEC filing URL so readers can inspect the source rather than relying only on our interpretation.
Why do transaction codes matter?
Form 4 uses codes to describe why ownership changed. Code P generally means an open-market or private purchase and code S generally means an open-market or private sale. Code A can identify an award, code M an exercise or conversion of a derivative security, code F shares used for an exercise price or tax liability, and code G a gift.
Those events can have very different meanings. Outfox will classify them separately instead of combining every acquisition into ‘insider buying’ or every disposition into ‘insider selling.’
How Outfox will use Form 4 data
Outfox will compare verified open-market activity with congressional disclosures, institutional holdings, and company context. We will show agreement and disagreement rather than turning a single filing into a recommendation.
What this information cannot tell you
- A filing reports a transaction; it does not disclose the person’s complete investment thesis.
- An insider may have other holdings, derivatives, tax considerations, or prearranged trading instructions.
- A transaction by one insider is evidence to investigate, not proof that a security will rise or fall.
Primary sources
- Investor bulletin: Forms 3, 4 and 5 (opens in a new tab)U.S. Securities and Exchange Commission · Link verified 2026-09-02
- General instructions for Form 4 (opens in a new tab)U.S. Securities and Exchange Commission · Link verified 2026-09-02
Keep learning
Educational information only. This guide is not personalized investment advice or a recommendation to buy, sell, or hold a security.