What a 13F shows, and what it misses
A 13F is the quarterly list of US-listed shares that a large investment manager owns. It’s the best free window into what famous investors hold, but it’s late, it’s partial and it only shows one side of the book.
Who has to file
Any institutional investment manager with discretion over at least $100m of “13(f) securities” must file a Form 13F with the SEC for each quarter. 13(f) securities are mostly shares, ETFs, listed options and some convertible bonds traded on US exchanges; the SEC publishes the exact list each quarter. Hedge funds, mutual fund companies, pension managers, banks, insurers and family offices that manage outside money all file.
When it’s filed
Within 45 days of each quarter end: in practice mid-February, mid-May, mid-August and mid-November, moving to the next working day if the 45th day is a weekend or US holiday. Many managers file on the last day. So a 13F tells you what a manager held on the last day of the quarter, between 6 and 20 weeks before you read it. Latest moves lists filings as they arrive, and each manager’s page shows when its next one is likely.
What it shows
- Each holding’s name, CUSIP (security code), number of shares and market value at quarter end.
- Call and put options, shown separately, by the value of the underlying shares rather than what the options cost.
- Whether the manager had sole, shared or no voting authority.
Values have been reported in whole dollars since January 2023; before that they were in thousands, which is why old filings look a thousand times smaller in some tools. Comparing one quarter with the last gives you the buys and sells, but only as changes in share count. A 13F doesn’t show prices paid, trade dates or anything traded and closed within the quarter.
What it misses
- Shares listed outside the US. Nestlé in Zurich, Novo Nordisk in Copenhagen or Diageo in London don’t appear unless the manager holds a US-listed version. For global investors this can be most of the portfolio. moatshark fills some of the gap from the full holdings that US mutual funds and ETFs report on Form N-PORT. How we do it.
- Short positions, cash, most bonds and private investments. A manager can look fully invested and in fact be hedged or sitting on cash.
- Positions given confidential treatment. The SEC lets managers delay disclosing a position they are still building, for up to a year.
- Everything between the quarter ends. A stock bought in April and sold in May never shows.
- Who in a large firm made the decision. A firm-wide 13F mixes every fund and account it runs.
Faster signals: Schedules 13D and 13G
An investor that passes 5% of a company’s shares has to say so much sooner than the next 13F. A Schedule 13D, for investors who may try to influence the company, is due within five business days of crossing 5%, and amendments within two business days of a material change. Passive holders file the shorter Schedule 13G; for most large institutions that’s due 45 days after the end of the quarter in which they crossed 5% (sooner above 10%). Both have been machine-readable since December 2024, which is how moatshark lists them on each manager’s page.
How to read one well
- Look at weights, not just names. A new holding at 0.1% of the portfolio is a toe in the water; one at 5% is a decision.
- Look at the change in share count. A holding’s value can rise because the price rose. moatshark’s change column uses shares, adjusted for splits.
- Check how long it has been held. Patient managers often build slowly over several quarters.
- Remember the lag. By the time you read it, the manager may have sold. Use 13Fs to find ideas to research, not trades to copy.
- See the whole picture. For managers who also run US funds, look at the fund portfolios too: that’s where the overseas holdings are.
Where to go next
- Every manager on moatshark, with what they own and what changed.
- Most owned, bought and sold across all of them, and every quarter since 2013.
- The SEC’s own guide: Frequently asked questions about Form 13F.