Key points
- 01A 13F is a delayed quarter-end snapshot of U.S.-listed long positions; it omits cash, shorts, private assets, and much of a manager's hedging book
- 02Berkshire reported $299.25 billion, with economic exposure concentrated in Apple, American Express, Alphabet, Coca-Cola, and Bank of America
- 03Duquesne reported $5.21 billion and kept Natera as its anchor while combining semiconductors, biotech, country ETFs, and options tactically
- 04Bridgewater reported $24.38 billion across 997 lines and shifted its disclosed long book toward S&P 500 ETFs while trimming several mega-cap technology holdings
- 05The useful lesson is not which overlapping ticker to copy, but whether a manager's concentration, turnover, and hedging logic fit the investor's own process
Source summary
Start by limiting what a 13F can tell us
Form 13F reports certain U.S.-listed securities held by qualifying institutional investment managers after each quarter. This comparison uses the June 30, 2026 filings and compares share counts with the preceding quarter.
Changes in reported value are not treated as trading flows. Market prices can change the value of an unchanged position, while the reported value of an option is not the same as cash invested or maximum loss.
Berkshire's filing also covers Berkshire Hathaway and multiple reporting managers rather than Warren Buffett's personal account. Bridgewater and Duquesne may hold cash, bonds, futures, shorts, private assets, or foreign securities that are absent from this view.
| Manager | Reported value | Largest exposure | Observed quarter-over-quarter move |
|---|---|---|---|
| Berkshire Hathaway | $299.25B | Apple 22.0% · American Express 17.1% · Alphabet combined 12.6% | Added both Alphabet share classes · trimmed Bank of America and Kroger |
| Duquesne Family Office | $5.21B | Natera 16.6% · TSMC 5.4% · STMicroelectronics 4.5% | Expanded to 95 lines · mixed biotech, semiconductors, country ETFs, and calls |
| Bridgewater Associates | $24.38B | SPY 16.3% · IVV 9.2% · Nvidia 3.2% | Added SPY and IVV shares · cut Amazon, Alphabet, and Broadcom shares |
Berkshire shows the persistence of concentration
Berkshire's largest economic exposures were Apple at 22.0%, American Express at 17.1%, both Alphabet share classes at a combined 12.6%, Coca-Cola at 10.9%, and Bank of America at 9.2%. Those five companies represented about 71.8% of reported value.
Share counts for Apple, American Express, and Coca-Cola were unchanged. Alphabet Class A shares rose 45.2% and Class C shares rose 658.3%, while Bank of America fell 5.9% and Kroger fell 22.0%.
This is not a static portfolio in which every core holding receives equal treatment. It looks more like a concentrated process that simultaneously preserves mature compounders, builds conviction in selected assets, and withdraws capital elsewhere.
Duquesne changes hypotheses within a quarter
Duquesne's largest reported position was Natera at $865 million, or 16.6% of the filing. TSMC and STMicroelectronics followed, while calls on an equal-weight S&P 500 ETF and a Brazil ETF also appeared among the larger lines.
The number of disclosed lines rose from 70 to 95. Bitdeer Technologies, Hyperliquid Strategies, UWM Holdings, and Fox appeared as new positions, while share counts in Cleveland-Cliffs and PureCycle Technologies increased substantially.
That structure cannot be explained by long-term company analysis alone. It suggests a tactical process that combines individual businesses, industry cycles, country exposure, and options to reshape probabilities and payoff asymmetry.
Bridgewater looks more like exposure design than stock picking
Bridgewater disclosed 997 lines, the broadest portfolio of the three. SPY and IVV represented 25.5% of reported value together, and their share counts rose 21.9% and 12.1%, respectively.
Over the same quarter, Amazon shares fell 53.8%, Alphabet Class A fell 33.8%, and Broadcom fell 28.2%. Exposure to Petrobras, Transocean, Halliburton, and other energy-related names increased.
The filing does not prove that Bridgewater lost conviction in technology. It does show that its disclosed U.S.-listed long book reduced several concentrated mega-cap positions while adding broad market beta and energy exposure.
Jamie's notes
Read the operating system before copying a holding
The most useful information is not the overlap among the three filings. Berkshire puts large weights behind the long-run economics of a few businesses, Duquesne replaces hypotheses quickly, and Bridgewater designs total exposure across hundreds of assets.
An investor who copies Berkshire's concentration, trades it at Duquesne's speed, and selects only a few names from Bridgewater removes the risk controls embedded in every original strategy. The guru's tickers remain, but the guru's system disappears.
Track three questions in the next filing
First, watch whether share counts move in the same direction over several quarters. A two-to-four-quarter sequence can say more about conviction than one new position.
Second, ask what risk a new holding adds or offsets. The same semiconductor stock can serve a different role inside Berkshire's concentration, Duquesne's option book, or Bridgewater's diversified system.
Third, state the missing pieces explicitly. A smooth story built without cash, shorts, or private assets can feel more precise while becoming less accurate.
Related notes
This is a personal research note, not investment advice