Warren Buffett's Berkshire Hathaway opened a new Delta Air Lines position in its 13F filing dated 2026-05-15, making it the fund's largest new bet at 1.01% of the portfolio. The filing also shows Alphabet as the largest increase at $10.01 billion and American Express as the largest trim.
The 13F Filing That Changed Berkshire's Portfolio
Berkshire Hathaway filed its quarterly 13F with the SEC on 2026-05-15, disclosing ten U.S. equity positions. The Berkshire 13F filing shows Delta Air Lines as the largest new position at 1.01% of the portfolio.
Alphabet Inc was added with a reported value of $10,014,229,467, the largest increase in the filing. The filing lists Apple as the top holding at 22.0% of the portfolio, followed by American Express at 17.4%. Total reported positions fell to ten, down from the prior quarter's count after three full exits.
The 13F reports only long U.S. equity positions, so cash and short positions remain undisclosed. Berkshire's latest 13F changes include new stakes in Delta, Alphabet, and Macy's.
Following the Paper Trail: How 13F Filings Reveal Smart Money Moves
Regulatory filings from large investors disclose quarterly holdings, though entry prices and holding durations remain undisclosed. — Photo by RDNE Stock project on Pexels
The SEC requires any institutional manager with over $100 million in AUM to file a 13F quarterly. HedgeFollow tracks over 10,000 institutional investors that file 13F to the SEC, according to its 13F page.
The 13F filing date is the official disclosure date; the SEC publishes it within 45 days of quarter end. The HedgeFollow platform claims to track 10,000+ funds and 100,000+ insiders. Each 13F lists holdings, shares owned, and market value, but not entry prices or intended holding periods.
The SEC's EDGAR database is the primary source for accessing raw 13F documents.
Berkshire's Pattern: Trimming Giants While Buying Airlines
The portfolio updates reveal a strategic rotation away from major financial holdings toward airline and technology investments. — Photo by RDNE Stock project on Pexels
American Express was reduced by $10,229,173,929 in reported value, the largest trim in the filing. Apple and Bank of America also saw reductions, with Apple still the top holding at 22.0%.
The three largest increases were Alphabet, Occidental Petroleum, and Coca-Cola, per the 13F changes. Visa was fully removed after representing 1.06% of the prior portfolio, a rare full exit for Berkshire.
Mastercard and UnitedHealth were also fully exited, marking a shift away from financial and healthcare names. The pattern shows Berkshire rotating out of large-cap financials into airlines and tech. Delta Air Lines' new stake at 1.01% suggests a fresh conviction in the airline sector.
Who Benefits From Public 13F Disclosures
Retail investors can study 13F data to see exactly what funds like Berkshire bought and sold. WhaleWisdom allows users to research and replicate the portfolios of the world's best investors, per its homepage.
Tools like the 13F Fund Performance Search let users filter by fund rating or AUM, according to WhaleWisdom. The 13F Stock Screener helps identify which funds own a specific stock, useful for following smart money trends. Regulators and journalists use 13F filings to monitor systemic risk and unusual concentration.
The 13F filing is a free, equal-access document for all market participants, unlike sell-side research.
What Happens Next: Key Dates and Disclosures to Watch
The next 13F filing window ends 45 days after the current quarter, so watch for the May 2026 deadline. HedgeFollow's platform lists fund managers, 3-year performance, and turnover, which can show if this pattern continues. Berkshire's next 13F could confirm whether Delta is a long-term hold or a tactical trade.
Investors should monitor quarterly changes in Alphabet and American Express to see if the trend persists. The SEC's EDGAR system will publish all 13F filings within the same 45-day window, enabling side-by-side comparisons.
FAQ
What are 13F filings and who is required to file them?
A 13F is a quarterly report filed to the SEC by any institutional investment manager with over $100 million in assets under management. It lists all U.S. equity holdings, giving a snapshot of that fund's long positions. The rule values transparency for investors who track what large funds are buying.
How often are 13F filings published and where can I find them?
13F filings are published quarterly, no later than 45 days after the end of each quarter. For example, a filing dated 2026-05-15 covers the first quarter of 2026. They are freely available on the SEC's EDGAR database, and aggregators like HedgeFollow re-publish them with additional analytics.
How can I track hedge fund holdings using 13F data?
You can use SEC EDGAR to read raw filings, or platforms like HedgeFollow and WhaleWisdom that track 10,000+ institutional investors. These tools let you search by stock or fund, view historical changes, and filter for performance. They convert raw data into tables showing top holdings, top buys, and top sells.
What are the limitations of 13F filings for retail investors?
13F filings are delayed, often by up to 45 days, so they may not reflect current positions. They only show long U.S. equity holdings; no short sales, foreign stocks, or options are disclosed. The reported value is as of the filing date, not market value today. Thus, they offer a historical, not real-time, view.
How do I interpret a 13F filing to identify a fund's top stock picks?
Look at the percentage of the portfolio each holding represents. A high percentage, like Apple at 22.0% in Berkshire's filing, signals a high-conviction position. Also check the 'new positions' and 'increases' sections. A new stake, such as Delta at 1.01%, shows fresh buying interest. Comparative changes reveal shifts in strategy.
What is the difference between a 13F filing and a 13D/G filing?
A 13F reports all U.S. equity holdings of any manager with over $100 million AUM, filed quarterly. A 13D or 13G is filed when an investor acquires more than 5% of a company's shares, disclosing intent (activist vs. passive). They serve different purposes: 13F shows a portfolio, while 13D/G shows ownership stake and plans.