How to Read a 13F
Last updated: 2026-06-07
Big institutional investors have to tell the public which U.S. stocks they own. They do it once a quarter, in a filing called a Form 13F, and those filings are where Compounder's superinvestor pages come from. A 13F can tell you a lot about how a serious investor is positioned. It can also mislead you if you take it at face value, so it helps to know what you're actually looking at.
What a 13F is
Any institutional manager running at least $100 million in U.S. stocks has to file a 13F with the SEC every quarter. The filing lists the firm's U.S.-listed stock positions as of the last day of the quarter: the stock, the share count, and the market value.
Line these filings up across a lot of well-known investors and you start to see overlap. The stocks that turn up in many portfolios at once are what we mean by consensus.
What you can learn from it
The most useful number on the page is position size. A stock that makes up 10% of a portfolio means something. A 0.2% sliver usually doesn't. Size is how an investor signals conviction, and the weighting puts it right in front of you.
Overlap is worth watching too. When several investors who think independently all hold the same company, that proves nothing on its own, but it's a reasonable place to start looking. And if you set a manager's filing this quarter next to last quarter's, you can see what they added to, trimmed, or sold outright. That direction of travel often says more than any single snapshot.
What a 13F leaves out
This is where people get tripped up. By the time you read a 13F it's already old news, and it only ever shows part of the picture.
For one thing, it can be up to 45 days stale. Managers get 45 days after the quarter closes to file, so the positions you're reading may already be weeks or months out of date.
It also shows only what a fund is long. Short positions never appear, which means a stock that looks like a big bet might actually be hedged against something else. The report is limited to U.S.-listed stocks and some options, so cash, bonds, foreign shares, and private holdings don't show up at all. And it's a single day's photo: the numbers are whatever the fund held on the last day of the quarter, not the average position and not what they own today.
How to actually use it
Treat a 13F as a lead, not an answer. The useful question isn't "what did they buy so I can buy it too." It's "why might someone thoughtful own this, and do I understand the business well enough to judge that for myself?"
Copying a holding outright ignores everything the filing doesn't tell you: what the investor paid, how long they mean to hold, how much risk they can stomach, what else is in the portfolio. By the time any of it is public, the price and the reasoning behind it may have moved on.
Compounder lets you see who holds a given stock and how that consensus shifts over time. It's a good way to find businesses worth a closer look. The looking is still up to you.