Berkshire Hathaway's 13F: What It Shows and What It Hides

Berkshire Hathaway's 13F is the quarterly report in which Warren Buffett's company discloses its US listed stock positions to the SEC. It is public, free and widely followed, but it is also narrower and more delayed than most readers assume, and in multiple recent years it did not even show the whole picture at the time it was filed.

This post covers what Berkshire's 13F actually contains, where to find it for free, why the SEC lets Berkshire keep some positions out of it for a while, and how to pull the filing as structured data instead of reading the SEC's raw filing index by hand.

Where to find Berkshire's 13F filings

Berkshire Hathaway Inc. files under SEC CIK 1067983, the same number used for every filing the company makes, not only its 13Fs. You can look up its filing history for free on EDGAR by searching that CIK and filtering by form type 13F-HR, which is the quarterly holdings report, or 13F-HR/A, which is an amendment to one.

Berkshire has filed a 13F-HR every quarter since the mid 1990s, soon after Section 13(f) of the Securities Exchange Act of 1934 required it. Each report has two parts: a short cover page naming the manager and the reporting period, and an information table that lists every qualifying position by security.

What a 13F from Berkshire actually covers

A 13F only reports "Section 13(f) securities," a defined list the SEC publishes and updates. For a conglomerate the size of Berkshire, that creates a large gap between the 13F and the business as a whole:

Reading only the 13F, a quarter where Berkshire adds to a position and a quarter where it starts building a brand new one can look identical in the information table. The only way to tell them apart is to compare the CUSIPs present in the current filing against the prior quarter's filing, which What Is a 13F Filing? covers in more detail for any manager, not only Berkshire.

When Berkshire's 13F is published

Like every other manager, Berkshire has 45 days after a calendar quarter ends to file. For the quarter ending June 30, that is a deadline of August 14; for the quarter ending September 30, November 14. The full deadline table for every quarter is in 13F Filing Deadlines and Why Holdings Data Is Always a Bit Stale.

Berkshire generally files close to its deadline rather than early, so a position reported in a given 13F can already be up to six weeks old, and Berkshire may have changed it by the time the filing becomes public.

Why a Berkshire 13F can hide a stock entirely

This is the part of Berkshire's 13F that catches people off guard: the information table is not always a complete list of what Berkshire bought that quarter, even for Section 13(f) securities.

SEC rules let an institutional manager request confidential treatment for part of a 13F while it is still accumulating a position, so that other investors cannot see the filing and trade ahead of it. If the SEC grants the request, the manager's public 13F for that quarter is filed with the position left out, and the full picture only appears later, once the manager amends the filing or the confidential period expires.

Berkshire has used this provision more than once in recent years. It is widely reported in financial media that Berkshire's 13F for the third quarter of 2020 initially omitted stakes that were only identified, once an amendment was filed, as Chevron and Verizon. The same pattern was reported again around Berkshire's 13F for the first quarter of 2024, when a previously undisclosed position was revealed to be the insurer Chubb after Berkshire had reportedly been building it for several quarters. None of those share counts or dollar figures are independently verified here; if you need them, pull Berkshire's own amended 13F-HR/A filings rather than a news summary.

Comparing Berkshire's quarters

Because a single 13F is a snapshot, the more useful read usually comes from comparing two consecutive quarters for the same CUSIP:

• New positions: a CUSIP present this quarter that was absent last quarter, keeping the confidential treatment gap above in mind.
• Exits: a CUSIP that disappears entirely.
• Changes in size: a difference in the shares field for a CUSIP that appears in both quarters.

Compare share counts rather than dollar values when you do this, since the value field also moves with the stock price between quarters, independent of whether Berkshire bought or sold anything.

Reading Berkshire's 13F as data

Browsing one 13F-HR at a time on EDGAR works if you only care about a single quarter. Comparing several quarters, or checking which other managers also hold the same stock as Berkshire, is slow to do by hand because the information table is published as XML.

SecFeed parses every 13F information table into rows and lets you filter by manager CIK. To pull Berkshire's reported holdings for the quarter ended June 30, 2026, sorted by value:

curl "https://secfeedapi.com/v1/form-13f/holdings?cik=1067983&period=06-30-2026" \
  -H "Authorization: Bearer YOUR_API_KEY"

Each row returns the issuer, its CUSIP, the reported value and share count, and the voting authority split:

{
  "filer_cik": 1067983,
  "filer": "BERKSHIRE HATHAWAY INC",
  "period": "06-30-2026",
  "issuer": "EXAMPLE TECHNOLOGIES INC",
  "cusip": "000000000",
  "value": 150000000000.0,
  "shares": 900000000.0,
  "sh_prn": "SH",
  "put_call": null,
  "vote_sole": 900000000.0,
  "vote_shared": 0.0,
  "vote_none": 0.0
}

The cover page fields, including the reporting period and whether a filing is marked as an amendment, come from /v1/form-13f?cik=1067983. In Python, you can pull two quarters and diff them by CUSIP to find new positions and exits:

from secfeed import Client

sf = Client("YOUR_API_KEY")
q2 = {r["cusip"]: r for r in sf.holdings_13f(cik="1067983", period="06-30-2026")}
q1 = {r["cusip"]: r for r in sf.holdings_13f(cik="1067983", period="03-31-2026")}
new_positions = [c for c in q2 if c not in q1]
exits = [c for c in q1 if c not in q2]
print("new:", new_positions)
print("exited:", exits)

For a worked, step by step version of this same query, including aggregating by CUSIP and computing portfolio weights, see Get a fund's 13F portfolio holdings by CIK, which uses Berkshire's own filings as the example. The dataset itself, with every field from the original XML, is documented on the 13F-HR manager quarterly holdings dataset page.

Frequently asked questions

What is Berkshire Hathaway's CIK number?

1. The SEC assigns one CIK to a filer across every form it files, so Berkshire's 10-Ks, 8-Ks and 13F-HRs all appear under the same number on EDGAR.

Does Berkshire's 13F show its whole portfolio?

No. It only shows Section 13(f) securities, which means US listed stocks, some listed options and similar instruments. It never shows Berkshire's wholly owned operating subsidiaries, its cash and Treasury bill holdings, most bonds, or any short positions.

Why did Berkshire's 13F have an unnamed stock?

The SEC can grant confidential treatment for a new position while a manager is still building it, so the public 13F omits that security until the confidential period ends or the manager amends the filing. This has been reported to apply to several Berkshire positions in recent years before each was eventually named.

How often does Berkshire file a 13F?

Once per calendar quarter, the same schedule that applies to any institutional manager with at least $100 million in qualifying securities. The deadline is 45 days after each quarter ends.

Is Berkshire's 13F data free to access?

Yes. It is a public filing on EDGAR at no cost. Services that charge for 13F data, including SecFeed, are charging for parsing, structure and the ability to query or compare it programmatically, not for the underlying filing.