A 13F is a quarterly report that every institutional investment manager with $100 million or more in US-listed stocks and similar securities must file with the Securities and Exchange Commission (SEC), listing its long positions at the end of the quarter [1]. It is due within 45 days of the quarter's end, so the filings for the quarter that ended September 30, 2026 are due by Monday, November 16, 2026, because November 14 falls on a Saturday [1]. 13Fs are the main public window into what funds such as Berkshire Hathaway (BRK-B) own, but they are delayed, leave out short positions and cash, and show only a snapshot.
Who files a 13F, and what does it include?
The requirement applies to institutional investment managers that exercise investment discretion over $100 million or more in "Section 13(f) securities" [1]. Managers include hedge funds, mutual fund companies, pension funds, banks, insurance companies and other firms that invest for clients or for themselves, such as Berkshire Hathaway.
The SEC publishes an Official List of Section 13(f) securities each quarter. It mainly covers US exchange-traded stocks, closed-end funds and exchange-traded funds, plus certain convertible bonds, options and warrants [1]. Each holding is listed with the issuer, share class, CUSIP identifier, number of shares and market value at the end of the quarter.
What a 13F does not show
- Short positions: managers report only long positions and may not net them against shorts [1].
- Mutual funds, foreign-listed shares, bonds and cash: open-end mutual funds and shares that trade only on non-US exchanges are not reported [1].
- Timing within the quarter: a position bought and sold between two quarter-ends never appears.
- Some positions, for a while: managers can ask the SEC for confidential treatment of a position, for example while still building it; since February 28, 2023 those requests must be filed electronically on EDGAR [1]. The position is disclosed later in an amended filing.
When are 13F filings due?
| Quarter ended | 13F deadline |
|---|---|
| March 31, 2026 | May 15, 2026 (Friday) |
| June 30, 2026 | August 14, 2026 (Friday) |
| September 30, 2026 | November 16, 2026 (Monday) |
| December 31, 2026 | February 16, 2027 (Tuesday) |
Source: SEC, Form 13F FAQ; a deadline that falls on a weekend or holiday moves to the next business day under Exchange Act Rule 0-3(a) [1].
The lag matters. A position held on September 30 may be disclosed as late as November 16, about seven weeks later, and the manager may have changed it in the meantime. Berkshire Hathaway filed its last two 13Fs on the deadline days, May 15 and August 14, 2026 [2][3].
What did Berkshire Hathaway's latest 13F show?
Berkshire Hathaway's 13F for the quarter ended June 30, 2026, filed on August 14, listed 89 entries worth $299.3 billion in total [2]. Comparing it with the March 31, 2026 filing, matched by each security's CUSIP, shows what changed [2][3]:
| Holding | Value, June 30, 2026 | Share of 13F value | Change in shares vs March 31, 2026 |
|---|---|---|---|
| Apple (AAPL) | $65.95B | 22.0% | Unchanged (227.9 million) |
| American Express (AXP) | $51.28B | 17.1% | Unchanged (151.6 million) |
| Alphabet (GOOGL, both classes) | $37.77B | 12.6% | +48.1 million, to 106.0 million |
| Coca-Cola (KO) | $32.51B | 10.9% | Unchanged (400 million) |
| Bank of America (BAC) | $27.54B | 9.2% | −30.2 million, to 483.4 million |
| Delta Air Lines (DAL) | $5.37B | 1.8% | +17.5 million, to 57.3 million |
| Kroger (KR) | $2.17B | 0.7% | −11.0 million, to 39.0 million |
| Constellation Brands (STZ) | None | 0% | Sold all 632,890 shares |
Source: Berkshire Hathaway Form 13F-HR information tables for March 31 and June 30, 2026; changes and shares of value are DataPorium calculations [2][3].
The filing shows several lessons about reading 13Fs. Issuer names can change between filings (Bank of America appears under two different names in the two reports), so positions should be matched by CUSIP, not name [2][3]. Values are at quarter-end prices, not at the price paid. And the top five positions made up 71.8% of the reported total, a concentration that tells more about the portfolio than the long tail of small holdings [2].
A 13F shows where a manager stood on the last day of the quarter, disclosed weeks later; it is a record of past decisions, not a live feed.
How do you use 13F data well?
Look at changes, not just holdings
The most informative entries are new positions, large additions and full exits, such as Berkshire's 48.1 million-share addition to Alphabet and its exit from Constellation Brands in the second quarter of 2026 [2][3].
Look at the crowd as well as the star
13F data can also be read the other way, by company: how many managers own a stock and how much. DataPorium's company pages aggregate it. For Apple, 6,519 13F filings reported positions worth $2.83 trillion (excluding options) for the quarter ended June 30, 2026, up from 4,796 filings in the first quarter of 2023 [4].
Know the limits before copying
- Delay: up to 45 days, plus however long since the quarter-end trade.
- Missing context: no shorts, hedges or cash, so a long position may be part of a hedged trade.
- Different goals: a manager's position size reflects its own portfolio, taxes and time horizon.
- Confidential positions: the most recent purchases may be withheld for a time [1].
Where to find 13F filings
- Search the manager's name on the SEC's EDGAR system and open filings of type 13F-HR; the information table lists the holdings [2].
- Check for 13F-HR/A amendments, which can add positions that were confidential.
- Use company-level data, such as the institutional ownership on DataPorium's Apple page, to see the number of holders and total value by quarter [4].
Berkshire Hathaway's own company page on DataPorium shows its stock price and financial statements alongside the holdings it reports [5].
Key takeaways
- Managers with $100 million or more in 13(f) securities must file a 13F within 45 days of each quarter-end [1].
- Third-quarter 2026 13Fs are due Monday, November 16, 2026, because November 14 is a Saturday [1].
- 13Fs show long US-listed positions only: no shorts, cash, mutual funds or foreign-only listings [1].
- Berkshire's June 30, 2026 13F listed $299.3 billion, with Apple at 22.0% and a 48.1 million-share addition to Alphabet [2][3].
- 6,519 13F filings reported Apple shares for the second quarter of 2026 [4].
Frequently asked questions
When are 13F filings released?
Within 45 days of each quarter-end, moved to the next business day if that falls on a weekend or holiday. For the September 30, 2026 quarter, the deadline is November 16, 2026 [1].
Who has to file a 13F?
Institutional investment managers with investment discretion over $100 million or more in Section 13(f) securities, such as hedge funds, banks, insurers and pension managers [1].
Do 13F filings show short positions?
No. Only long positions are reported, and they may not be netted against shorts [1].
What did Berkshire Hathaway buy in the second quarter of 2026?
Its 13F shows it added 48.1 million Alphabet shares and 17.5 million Delta Air Lines shares, reduced Bank of America and Kroger, and sold its Constellation Brands stake [2][3].
Sources & References
- [1] U.S. Securities and Exchange Commission, Frequently Asked Questions About Form 13F (accessed October 13, 2026)
- [2] Berkshire Hathaway Inc., Form 13F-HR for the quarter ended June 30, 2026 (filed August 14, 2026)
- [3] Berkshire Hathaway Inc., Form 13F-HR for the quarter ended March 31, 2026 (filed May 15, 2026)
- [4] DataPorium Apple (AAPL) stock page (institutional ownership from 13F filings)
- [5] DataPorium Berkshire Hathaway (BRK-B) stock page