How to read a 13F filing
Every quarter, the largest US fund managers tell the SEC which listed shares they held on the last day of the quarter. That report is Form 13F. You can read a manager's book from it, but only part of it, and with a delay of up to 45 days.
Who files
An institutional investment manager files a Form 13F once it exercises investment discretion over $100 million or more in Section 13(f) securities, according to the SEC's Form 13F FAQ. Hedge funds, mutual fund companies, pension funds, banks and insurers all fall under the rule when they cross that line. A manager that crosses it during a year files for the quarter ending on 31 December of that year and for each quarter after.
The 45-day delay
A manager files within 45 days after the end of each calendar quarter. The holdings show the position on the last day of that quarter. So a filing that arrives in mid-February shows what the manager held on 31 December, and the manager may have sold since.
What is in it
The filing has a cover page and an information table with one row per holding: the issuer, the class of shares, the CUSIP code, the market value, the number of shares, and how the voting authority is split. A row marked PUT or CALL is an option position.
Only securities on the SEC's official list of Section 13(f) securities count. The SEC updates that list every quarter, and most entries on it are shares traded on US exchanges.
What is not in it
- Short positions. The FAQ tells managers to leave them out, and not to subtract them from the long positions either.
- Cash, and anything else that is not on the 13(f) list.
- Small holdings: a manager may skip a holding below both 10,000 shares and $200,000.
- Positions under confidential treatment. A manager can ask the SEC to keep a holding out of the public filing for a time.
A manager whose holdings all appear on another manager's report files a 13F notice instead: a cover page with no information table.
Reading it with care
Compare two quarters and you see new, larger, smaller and closed positions. You do not see when in the quarter the manager traded, at what price, or what it holds on the other side. A manager that holds a stock and shorts it through a derivative shows only the long half.
13F filings on this site
Hedge Funds shows the 13F holdings of a fixed list of large managers, quarter by quarter, with the positions that changed and the stocks several of them hold. One example worked through: what is Berkshire Hathaway buying?. Company insiders report their own trades on a Form 4 within two business days instead. Corporate lobbying, a different US filing, is explained in how US lobbying disclosure works.
Checked against the regulation and the regulator’s own pages on Oct 31, 2026. This guide explains the rules; it is not legal or investment advice.
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