Four times a year, the world's largest investment managers hand the public a snapshot of their US stock portfolios. That snapshot is Form 13F. It is free, it is official, and it is the raw material behind every "what is Buffett buying" headline you have ever read. Yet most people have never opened one. This guide explains what a 13F filing is, where to find it, and how to read it without fooling yourself.
What a 13F filing is
Form 13F is a quarterly report required by Section 13(f) of the Securities Exchange Act of 1934. Congress added the requirement in 1975 to give the public and regulators visibility into the holdings of large institutional managers.
The rule applies to institutional investment managers that exercise investment discretion over at least $100 million in so-called Section 13(f) securities. That group includes hedge funds, mutual fund managers, pension managers, banks, insurance companies and large family offices. The filing is due within 45 days after the end of each calendar quarter. The SEC explains the mechanics in its official Form 13F FAQ.
Section 13(f) securities are, roughly, US exchange-traded stocks, certain ETFs, certain convertible bonds, and exchange-traded options on those securities. The SEC publishes an official list of covered securities every quarter. If a security is not on that list, it does not appear in the filing.
Three form variants exist. Form 13F-HR is the standard holdings report. Form 13F-NT is a notice that says another manager reports the holdings instead. Form 13F-HR/A is an amendment that corrects or restates an earlier filing.
Where to find 13F filings
Every 13F filing lives on SEC EDGAR, the commission's free public filing system. Two entry points work well.
First, the EDGAR company search lets you look up a manager by name or CIK number and filter by form type 13F-HR. Each filer has one CIK, so once you know it you can pull every quarter of history.
Second, EDGAR full-text search lets you search across filings. It is useful when you know a fund's brand name but not its exact legal filer name, which are often different.
One practical warning. Fund brands and legal filers rarely match one to one. A famous investor may file under a management company name you have never heard of, and one firm can have multiple filing entities. Confirm you have the right CIK before you compare quarters.
How to read the holdings table
The heart of a 13F is the information table. Since 2013 it is filed as structured XML, and EDGAR also renders it as a readable web page. Each row is one position and carries these columns:
- Name of issuer and title of class. The company and the share class, for example common stock versus a specific class.
- CUSIP. The security identifier. This is the reliable key for matching positions across funds and across quarters, because company names get abbreviated inconsistently.
- Value. The market value of the position at quarter end.
- Shares or principal amount. The position size in shares.
- Put or call flag. If the row is an option position, this column says whether it is a put or a call. A put row is not a bullish bet, so never skip this column.
- Investment discretion and voting authority. Whether the manager decides alone or shares control, and how voting power splits.
Reading one filing in isolation tells you what a fund held on the last day of the quarter. The real information is in the change between two filings. Line up the current quarter against the prior quarter by CUSIP and classify every position into four buckets:
- New buys. In the current filing, absent from the prior one.
- Adds. Held in both, share count went up.
- Trims. Held in both, share count went down.
- Exits. In the prior filing, gone from the current one.
Also look at position weight. A new buy that is 8 percent of a concentrated portfolio says far more than a 0.1 percent line in a fund with three thousand rows. Compare share counts, not dollar values, when judging whether a fund bought or sold. A position's dollar value can rise purely because the stock went up.
What a 13F does not show
This is where most misreadings happen. A 13F filing shows long positions in US-listed 13(f) securities and nothing else. It does not show:
- Short positions. A fund can be net short a stock it appears to hold.
- Cash. There is no cash line in a 13F.
- Bonds and credit. Corporate bonds, treasuries and loans are absent.
- Foreign-listed shares. A stock listed only in Hong Kong or Frankfurt does not appear, even if the position is enormous. ADRs traded on US exchanges do appear.
- Derivatives beyond listed options. Swaps and other private contracts are invisible.
- Intra-quarter trading. The filing is a quarter-end snapshot. A fund can buy and fully sell a stock inside a quarter and leave no trace.
There is also the timing gap. Because the deadline is 45 days after quarter end, and most managers file at or near the deadline, the positions you read can be up to 135 days old at the moment you read them. A manager may also request confidential treatment from the SEC to delay disclosure of a position it is still building, which is why a large new stake sometimes appears in an amendment months later.
Common mistakes to avoid
A few errors show up constantly when people first work with 13F data.
Treating a put option row as a long position is the classic one. The put or call column exists for a reason. Confusing dollar-value changes with buying is the second. Always compare shares. Ignoring 13F-NT and combined filings is the third, because holdings may sit under a different filer than expected. And assuming a filing reflects today's portfolio is the fourth. It reflects a date at least six weeks in the past.
Finally, remember what the data is for. Academic and practitioner studies of 13F-copying strategies come to mixed and often negative conclusions, largely because of the reporting lag. The filings are best used as a research lead. They tell you where experienced, well-resourced investors have put real money, and that is a strong reason to study a company. It is not a reason to buy it blind.
Free tools that make this easier
You can do everything above with EDGAR alone, and every serious workflow should end at the primary source. For convenience, two free sites are worth knowing. Dataroma tracks a curated set of value-oriented superinvestors and presents their holdings and changes cleanly. WhaleWisdom covers a much broader filer universe with screening and history, with some features behind a paid tier. Both build on the same EDGAR filings you can verify yourself.
The next step beyond reading one fund is comparing several. When multiple managers with different styles file the same new buy in the same quarter, that overlap is the most useful signal 13F data produces, and it is invisible when you read filings one at a time.
The Smart-Money 13F Consensus Report does that comparison for you: it distills the latest filings of six top managers into one ranked consensus table. Get the free preview.
DataSignals Lab publishes data and research. This is not investment advice.
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