How to Read Form 13F Without Overreading It
Form 13F is a quarterly report of certain holdings. It is a useful document and a widely misread one. This guide explains what it establishes, what it does not, and the four places readers most often go wrong.
Start with the three dates
Three different dates matter, and confusing them causes most misreadings. The position date is the single day the report describes — everything in it is true of that day and no other. The disclosure date is when the report became public. Regular quarterly reports are due within 45 days, with weekend and holiday adjustments; filings can arrive earlier and amendments later. The report does not show subsequent trades. The market-context date is any later date whose prices someone applied afterwards to make figures comparable — those prices were never filed values.
A report is not out of date because it is old. It describes one specific day, and it keeps describing that day forever. The mistake is reading it as a description of today.
Four traps, with the worked examples
- 01
A new row is not proof of a new purchase
These reports only cover securities on an official list. If a company was not on that list last quarter, its absence tells you nothing about whether the filer held it — the two quarters are structurally non-comparable. When a company joins the list, it appears as a new row on the first report after it becomes reportable.
- 02
A bigger number is not proof of more shares
A holding is reported twice: a share count and a value. The value moves whenever the price moves, even if the share count never changes. If you only read the value, an unchanged position looks like a decision. Check the share count before you conclude anything about buying or selling.
- 03
Counting rows is not the same as weighing them
A filing can have thousands of rows where a minority of them carries most of the reported value. Counting rows and weighing value are different questions with different denominators, and they can give opposite answers about what the filer mostly holds.
- 04
A complete filing can still be silent
Some things are simply not fields on the form. Written options are excluded, short stock is excluded, and strike and expiry are absent. A filing can be accurate, complete, and reconciled to the dollar and still not tell you which way a filer is leaning.
Identifiers, issuers, and why the difference matters
A CUSIP is the code that identifies one specific security. An issuer is the company behind it. One company can have several share classes, each with its own CUSIP, so “the top five holdings” can mean two different numbers depending on whether you count securities or companies. Neither is wrong; they answer different questions. A concentration figure without its basis stated is not a fact you can use.
Some rows are marked with a PUT/CALL designation, meaning the row reports an option rather than the security itself. Rows without that designation are a mixed group — domestic common stock, depositary receipts, ordinary shares of foreign issuers, and principal-amount instruments — and should not be described collectively as common stock.
The five labels we use on every figure
- Filed fact
- Literally in the filing.
- Verified derivation
- Calculated by us from filed inputs, with the formula shown.
- Market context
- Prices applied afterwards. Never filed values.
- Interpretation
- Our editorial judgement, attributable to us.
- Unresolved
- An explicit gap. Stated, not omitted.
See the questions applied to a real filing
- All reviewed dossiers
- SpaceX — Newly visible does not necessarily mean newly bought.
- Berkshire Hathaway — The value moved even when the reported shares did not.
- Citadel Advisors — Most of the value sat in reported options — and direction still can't be recovered.
- Harvard Management Company — A first appearance follows reportability, not a decision to buy.
Informational and educational only. Not investment advice, and no recommendation or performance claim is made or implied.