How to Read 13F Filings — The Limits to Know When Looking at What Buffett Bought

1. What is a 13F?

A 13F (Form 13F-HR) is a holdings report that, under U.S. Securities and Exchange Commission (SEC) rules, institutional investors managing $100 million or more in covered securities such as U.S.-listed stocks must file every quarter. Filers include Warren Buffett’s Berkshire Hathaway, hedge funds such as Bridgewater, and large public pension funds and sovereign wealth funds.

• Filing deadline: Within 45 days of quarter-end. That is why filings cluster in mid-February, May, August and November.
• Original source: These are public records that anyone can view for free on the SEC’s electronic filing system (EDGAR).
• This site’s Big Investors page reads the original EDGAR filings directly and compares the latest quarter with the previous quarter for 12 investors.

2. What a 13F shows

3. The limits of 13F filings — what to keep in mind

1. Delayed information: The data are as of quarter-end and come out 45 days later, so by the time they are public, up to a month and a half has passed. The position may have been sold in the meantime.
2. Only part of the picture: Short sales (trades that bet on a falling share price), bonds, stocks traded outside the U.S., cash and so on do not appear. If the strategy is to buy on one side and hedge (offset risk) on the other, the intent cannot be known from a 13F alone.
3. No purchase prices: When and at what price shares were bought is not shown. Only the quarter-end market value is.
4. Small positions: Large funds hold many “trial” positions that make up less than 0.1% of the total. Look at the weight in the portfolio rather than the dollar amount.
5. Multiple portfolio managers: At large institutions, several managers invest separately, so a position may not reflect the judgment of the one famous investor.

4. How to read them

• New positions and complete exits: These get the most attention because they can signal a change of view.
• Stocks whose weight changed significantly: Changes in the weights of the top 10 holdings are key.
• Common moves by multiple investors: A stock that several investors moved in the same direction is more meaningful than one investor’s move. The “Common Moves” section on the Big Investors page shows this.
• Read alongside 13D and 13G: An investor whose stake in a company exceeds 5% must separately file a 13D (with intent to influence management) or a 13G (passive investment), and these come out much faster than a 13F.

5. Why “copycat buying” is risky

The strategy of buying the same stocks after seeing a 13F has major limits: the information is late, and each investor has different time horizons and risk management methods. Even for the same stock, the situation of a fund managing tens of billions of dollars is completely different from that of an individual. A 13F is best used as reference material for seeing trends in “which industries and companies are attracting interest.”

This article explains how to read 13F data. It is not a recommendation to buy or sell any particular stock.