How to read a 13F filing: what Buffett and the funds own

Every quarter somebody writes that Warren Buffett just bought something. What they have read is a 13F, a list of shares Berkshire Hathaway held on one day, published weeks afterwards. Here is how to read one properly, on Berkshire's own filing for Q2 2026, with every figure traced to the filing and a stated verdict at the end of each step.

Four times a year, every large money manager in the United States has to publish a list of the shares it owns. The list is free, it is on the SEC’s website, and almost every article written about it gets one of three things wrong: how old it is, what it leaves out, or what it says about price.

I read it the way I read any filing, in order, on one real example. Berkshire Hathaway is the one people search for, so that is the one I use.

1. 01

   What is a 13F filing?

   A 13F is a quarterly holdings report that every institutional investment manager with more than $100 million in US-listed shares must file with the SEC. It lists each position held on the last day of the quarter: the company, the number of shares and their value on that day. It is due within 45 days of the quarter ending.

   The names are worth getting straight, because searching for the wrong one turns up nothing. The rule is SEC Form 13F; the document a manager actually files is a 13F-HR, where HR stands for holdings report; and what it produces is the raw material behind every article about hedge fund holdings and every institutional ownership figure you have seen quoted for a stock. All three phrases describe this one screen.

   That is the screen at the top of this post. Berkshire’s filing for Q2 2026 was disclosed on 14 August 2026 and reports $299.25B of disclosed equity across 29 positions. The page is careful about the date in a way most coverage is not. Those positions are 77 days old as I write, and the next filing is not due until about 14 November.

   The line under the name matters too. Most of Berkshire’s value sits in companies it owns outright, like its railroad and its insurers, and none of them appear in a 13F. This is the listed shares, not the company.

   Try itBrowse the tracked managersForty-six well-known managers, each with their latest filing. None of the pages need an account to open.

   The read: Not a signal

   A snapshot of one day, published weeks later, and nothing more than that.

   Nothing on this screen says what Berkshire owns today. It says what Berkshire owned on 30 June 2026, and the first job is to hold on to that date before any of the positions start to look like news.

2. 02

   What does a 13F leave out?

   The list of what is missing is longer than people expect, and I keep it in front of me every time I open one of these.

   • Short sales. A manager betting against a company never has to say so.
   • Anything not listed in the US. Shares traded only on a foreign exchange, bonds, cash and private businesses are all outside the rules.
   • Trades inside the quarter. Buy in April and sell in May, and neither appears anywhere.
   • Some positions, for a while. A manager can ask the SEC to keep a holding confidential while it is still being built, and file it later.
   • Everything since the quarter ended. By the time the next one is due, the picture is four and a half months old.

   The most current public list of what Berkshire owns was already six weeks old on the day it was published.

   None of that makes a 13F useless. It makes it a record of decisions made in the past, which is a fine thing to read, as long as nobody mistakes it for a live feed.

   A 13F is not a Form 4, and the difference is speed

   The other filing people mean when they say “I saw what they bought” is a Form 4, and confusing the two is how a stale list gets read as news. A Form 4 is filed by a company’s own officers, directors and large shareholders when they trade their own company’s stock, and it is due within two business days. A 13F is filed by outside managers about everything they hold, and it is due within 45 days of a quarter that has already ended.

   So they answer different questions on different clocks. Form 4 tells you what one named person inside one company did this week. A 13F tells you what a large outside investor held up to four and a half months ago, across their whole US book. Neither substitutes for the other, and only one of them is ever close to current. I walk through the insider side of this on Microsoft in the insider step of how I read a company, where the interesting problem is separating a real purchase from shares that merely vested.

   The read: Worth watching

   More than it includes, and every gap points the same way: toward looking more certain than it is.

   A short position, a trade made and reversed inside the quarter, and a holding listed abroad are all invisible. So is anything bought after 30 June. A filing that looks like a whole portfolio is a partial one that has been sitting in a queue.

3. 03

   How do I see everything one investor holds?

   Open the manager and read the positions largest first. The weight column is the one I read before the dollar value, because it says how much each position matters to this manager rather than how big it is next to everyone else’s.

   

   Close

   Apple is the largest line at $65.95B, or 22.04% of the book. American Express is 17.14%, Coca-Cola 10.86%, Alphabet’s class A shares 9.41% and Bank of America 9.20%. The page puts the five together at 68.65%.

   One thing to watch for in any 13F: a line is a security, not a company. Alphabet appears twice here, as GOOGL at 9.41% and GOOG at 3.21%, because the two share classes are separate securities. Lennar and Liberty Live do the same thing. Twenty-nine lines is not twenty-nine companies.

   Try itOpen Berkshire Hathaway's filingThe page shows every quarter back to 2013. Pick an older one and see how different the top five looked.

   The read: Not a signal

   A concentrated book, and concentration is the only thing this list states outright.

   Five companies are more than two thirds of the disclosed book. That describes how Berkshire's listed holdings are arranged. It says nothing about whether any of them were good decisions, and nothing about what has been done with them since June.

4. 04

   What changed since the last quarter?

   The change column is where most of the coverage comes from, so it is worth reading across many managers at once rather than one.

   

   Close

   Across the 44 tracked managers who had filed for Q2 2026, the funds opened 475 positions and exited 382. Visa, Amazon and Microsoft were bought by the most managers, ten each.

   Alphabet is the interesting row. Its class A shares were the stock sold by the most tracked managers, 12 of them. In the same quarter Berkshire added to its own, and that position, at $28.16B, heads the list of biggest single buys. Its trimmed Bank of America stake, at $27.54B, heads the sells. Read those two lists carefully: they rank a position by what it is worth, not by how much of it moved.

   Try itSee what the funds did last quarterThe page always shows the most recent quarter. It updates as filings arrive, so the count of managers who have filed changes through the 45 days.

   The read: Both

   The direction of every move is a fact. The reason for any of them is not in the filing.

   Berkshire added to Alphabet by 45.24% and trimmed Bank of America by 5.89%. Both are real. Whether either was about the company, taxes, a rebalance or a person leaving the firm is something the filing does not record, and any sentence that supplies a reason is a guess wearing the filing's authority.

5. 05

   Who are the big holders of one stock, and do they agree?

   The same data read from the other direction: start from a company and list the managers who filed a position in it. This is the view most sites label institutional ownership, and it is built from exactly the filings above rather than from a separate source. I use Alphabet, because the last step left it with buyers and sellers pulling opposite ways.

   

   Close

   23 tracked managers held Alphabet at the end of June. Berkshire added 45.24%, taking the position to 9.41% of its book. Dodge & Cox added 0.32%, which is housekeeping. Bill Nygren’s Harris Associates trimmed 25.36%, and Chase Coleman’s Tiger Global trimmed 45.39% of a position that is still 8.65% of its book.

   The share-of-book column matters here for the reason I gave in the ownership step of how I analyze a company: a position at 2% of a book is a place to keep money, and one at 9% is a view.

   Try itSee who holds a company you ownThe holder list is on the company page of any US ticker, under tracked investors.

   The read: Both

   They rarely agree, and a quarter where they split is more common than one where they move together.

   Berkshire added 45.24% to its Alphabet position in the same quarter Tiger Global trimmed 45.39% of its own. Two serious investors, the same company, opposite decisions. The only honest reading of a holder list is that it records disagreement, and a headline that picks one side has chosen which filing to believe.

6. 06

   What price did they pay?

   This is the question I get asked most, and the answer is the one people like least: no 13F contains a purchase price. Not an average, not a range, nothing.

   

   Close

   What can be said honestly is narrower. Berkshire first disclosed Alphabet’s class A shares in Q3 2025, and in the quarters that position grew, the stock ended those quarters between $243.10 and $357.37. The shares could have been bought below, above or anywhere between, on any day of those quarters.

   The same table answers a better question, which is how patient this book is. The median position has been disclosed for 16 quarters, and 14 of the 29 have never been reduced. Five were already there in the earliest filing on record, so their real start is older than the product can see.

   The read: Worth watching

   Unknown, and anyone quoting a fund's cost basis from a 13F has made it up.

   The filing records shares and a value on one day per quarter. The range this page shows is where the stock closed the quarters the position grew in. It bounds the building of a position without describing it, and its midpoint is not an average cost either.

7. 07

   Does following the filing tell you anything?

   The last thing I check is the one that stops me treating any manager’s list as a set of instructions: what the disclosed positions actually did, quarter end to quarter end.

   

   Close

   Over the 20 quarters to Q2 2026, Berkshire’s disclosed book repriced by 61.79%. The S&P 500 moved 74.45% over the same quarter ends.

   I would not build anything on that comparison, and the product does not either. It weights positions by their value at the start of each quarter, ignores everything bought and sold inside one, and leaves out the cash, the bonds and the businesses Berkshire owns outright. What it does settle is that a famous name on a list does not make the list a shortcut.

   Here is what I actually take from an afternoon with a 13F.

   • Berkshire’s listed book is concentrated, patient and slow to change, and all of that is visible without an account.
   • It added to Alphabet in Q2 2026, in a quarter when more tracked managers sold Alphabet than any other stock.
   • Nothing in the filing says why, what was paid, or what has happened since 30 June.

   That last line is the whole discipline. A 13F is a very good record of what careful people decided months ago, and it is a poor guide to what anyone should do with a stock today.

   Try itSee what an account addsThe free plan does not expire and asks for no card. The complete position lists and the full quarter activity are on the paid plans.

   The read: Not a signal

   It tells you what was held. It does not tell you what copying it would have earned.

   The disclosed book repriced by less than the S&P 500 over five years. That is not Berkshire's return, and it is not a copier's return either, because a copier buys up to 45 days late at a different price. The number is worth knowing as a correction to the idea that the list is a shortcut, and worth nothing as a forecast in either direction.