13F Filings: What the Big Funds Are Buying, and How to Actually Use It
Every quarter, large investment managers have to disclose their stock holdings. Here's what a 13F shows, what it hides, and how a regular investor can get real use out of it.
Four times a year, the largest money managers in the U.S. have to show part of their hand. Hedge funds, pension funds, endowment managers, bank trust departments, and Berkshire Hathaway all file a report with the SEC listing the stocks they hold. That report is the Form 13F, and it’s free for anyone to read.
I started using 13Fs to see where the stock trends were heading, and they turned out to be most useful when the market was volatile. When prices are swinging and every headline disagrees with the last one, it helps to see what large, patient investors actually did with their money instead of what commentators said they should do. Used that way, a 13F is a great research tool. It works much less well as a list of stocks to copy, and it helps to know why.
What a 13F actually is
Section 13(f) of the Securities Exchange Act requires any institutional investment manager with at least $100 million in qualifying securities to file a Form 13F. The filing is due within 45 days after the end of each calendar quarter. It lists every qualifying position the manager held on the last day of that quarter: the company name, the number of shares, and the market value.
“Qualifying securities” mostly means U.S.-listed stocks and ETFs, plus some options and convertible bonds. The SEC publishes the official list.
So when Berkshire Hathaway files its 13F in mid-February, it shows what Berkshire’s equity portfolio looked like on December 31. By comparing that filing with the previous quarter’s, you can see which positions were started, added to, trimmed, or sold completely.
What it doesn’t show
This is the part most “copy the billionaires” articles leave out. A 13F is a partial snapshot, and the missing parts matter:
- It’s old by the time you see it. A filing can arrive up to 45 days after the quarter ends, and it reflects holdings on one single day. A position bought in early January might not appear until mid-May, and it could already be gone by then.
- Long positions only. Short sales don’t appear. If a fund holds a stock as one side of a hedged trade, the 13F shows the long side and hides the short side.
- No cash, no bonds, no foreign-listed stocks. You can’t tell whether a manager is 95% invested or sitting on a large cash pile, which is often the more interesting fact in a volatile market.
- No reasons. The filing tells you what was held, never why. A position might be a high-conviction bet, a tax move, a hedge, or a client’s request.
- Confidential treatment. Managers can ask the SEC to delay disclosing a position they’re still building. Some trades show up late, in an amended filing.
- Options are fuzzy. Put and call positions are reported by the value of the underlying shares, which can make a small bet against a stock look like a large bullish one.
None of this makes 13Fs useless. It just means they answer the question “what did this manager own on this date?” and not “what should I buy today?”
How I use it: reading the trend, especially when markets are rough
The most useful thing a 13F shows is how managers repositioned during a turbulent quarter. When the market sells off, everyone has an opinion. The next round of 13Fs shows what money actually did: which sectors experienced managers added to while prices were down, which crowded positions they quietly cut, and whether several unrelated funds moved in the same direction.
That last point matters most. A single fund buying a stock is an anecdote. When a number of well-regarded managers with different styles all add to the same sector in the same quarter, that’s a trend worth looking into. I use 13Fs to find those patterns, and then I do my own research on whether the idea still holds up at today’s prices.
Using it for idea generation
The healthiest way to use a 13F is as a starting point for research:
- Pick a few managers whose approach you respect and whose style fits yours. A long-term value investor’s picks don’t fit well in a short-term trading strategy, and the reverse is also true.
- Look at new positions and large increases, not just the biggest holdings. The top of a portfolio is often a position bought years ago. The changes show current thinking.
- Treat anything you find as a question, not an answer: Why might they own this? Is that reason still true at today’s price? Then read the company’s own filings.
If the price has already moved a lot since the end of the quarter, you’re not getting the deal the manager got. That alone rules out a lot of copycat trades.
Checking the funds you already own
13Fs can also show what the professionals you pay are actually doing. If you own an actively managed fund, looking up the manager’s 13F can tell you whether that “active” portfolio is quietly a close copy of the index you could buy for a fraction of the fee.
One caveat: a 13F covers a manager’s whole firm, not one fund. For a specific mutual fund or ETF, the better source is its own holdings report (Form N-PORT, which is also on EDGAR) or the holdings page on the fund’s website.
Where to look
- SEC EDGAR is the original source. Search for the manager by name and filter for “13F-HR” filings. It’s free and authoritative, but the raw holdings tables are awkward to read.
- Dataroma tracks a curated list of well-known value investors and shows their quarterly buys and sells in a clean format. It’s a good place to start.
- WhaleWisdom covers a much wider set of filers and lets you compare quarters, see which stocks many funds are buying at once, and track changes over time. The free tier is enough for most people.
Whatever tool you use, check the filing date and the “period of report” date. Those two dates tell you how old the information really is.
The short version
A 13F is a free, legally required look at what big investors owned at the end of last quarter. It’s excellent for spotting trends, especially after a volatile quarter when you want to see where real money moved. It’s also a good way to find ideas to research and to check whether the active funds you pay for are actually active. What it can’t do is tell you what to buy today. It’s delayed, incomplete, and it doesn’t include the reasons. If you use it as the start of your own research, not a substitute for it, it’s one of the best free research tools a regular investor has.
Not investment advice — just notes on how a public data source works, not a recommendation for your specific situation.