What Is a 13F Filing? A Complete Guide

Form 13F is a quarterly report that large institutional investment managers must file with the U.S. Securities and Exchange Commission (SEC). It discloses the U.S.-listed equity positions those managers held at the end of each calendar quarter, giving the public a delayed but detailed look inside the portfolios of hedge funds, sovereign wealth funds, pensions and other big investors.

Who has to file a 13F?

The requirement comes from Section 13(f) of the Securities Exchange Act of 1934. Any institutional investment manager that exercises investment discretion over $100 million or more in "Section 13(f) securities" — mostly U.S. exchange-listed stocks, certain options, ETFs and convertible notes — must file. Once a manager crosses that threshold, it files every quarter for the rest of the year.

This is why the same well-known names — Berkshire Hathaway, Citadel, Bridgewater, sovereign funds like Norges Bank — appear every quarter. It is also why passive index giants show up: the rule is about assets under discretion, not investment style.

What does a 13F actually report?

A 13F lists, security by security:

• The name of the issuer and the class of security
• The CUSIP (a nine-character identifier for the security)
• The market value of the position at quarter-end
• The number of shares (or principal amount)
• Whether the position includes put or call options
• Voting authority over the shares

Crucially, a 13F reports long positions only, and only in the specific set of securities the SEC designates. It is a snapshot as of the last day of the quarter.

Why do investors care?

13F filings are one of the only windows into what sophisticated, well-resourced investors are actually buying and selling. By comparing this quarter's filing to the last, you can see which positions a fund added, trimmed, opened or exited. Aggregating across many funds reveals crowded trades, contrarian bets and shifting sector preferences.

That said, 13F data is backward-looking. To understand what it does *not* show, read our guide on the limitations of 13F data, and to interpret a filing line by line, see how to read a 13F.