Francesco Di Costanzo
Back to shorts

(6) Borrowed Time: The Horizon Mismatch That Ended Situational Awareness

/5 min read

A Decade-Long View on Overnight Money

Situational Awareness LP financed a multi-year view of the AI build-out with money that was repriced every morning, and the financing decided the outcome. The fund run by Leopold Aschenbrenner was up 439% net for 2026 through the end of June, according to an investor letter dated 24 July reported by the Financial Times, and press estimates of its size ranged from $20bn to a peak near $45bn at the start of July. By the morning of 30 July, after margin calls from Goldman Sachs, JPMorgan Chase and Bank of America, the entire public equity book, longs and shorts together, had been sold to Citadel in a single block trade, and assets stood near $10bn. Every specific figure in that sequence comes from people described as familiar with the matter; the fund has not commented.

Press reports put the borrowing at roughly four times capital, a figure the fund never disclosed. At that level the manager does not choose the holding period. The prime broker does. Aschenbrenner's 24 July letter told investors the drawdown had created opportunity ahead of catalysts including a potential Anthropic listing, and asked for fresh commitments. Within four trading days the collateral desks had answered the same question differently, and their answer was the one with settlement mechanics attached.

The Thesis Was Never the Variable That Moved

AI infrastructure demand guidance rose through the drawdown. Microsoft, Alphabet, Meta and Amazon guided to roughly $710bn to $725bn of combined 2026 capital spending, up from about $402bn in 2025. Samsung reported a quarterly profit larger than Nvidia's and guided operating profit up 1,800%, and its shares still fell 8% on the day. What compressed was valuation and financing terms. The Philadelphia Semiconductor Index fell more than 20% from its late-June record after doubling from its March low, and on 28 July the Kospi dropped about 10% intraday on Chinese memory competition and doubts about AI payback periods, tripping a circuit breaker.

That distinction is where the fund's structure failed it. Brunnermeier and Pedersen showed in the Review of Financial Studies that margin requirements are destabilising because funding liquidity and market liquidity reinforce each other, producing spirals in which borrowers sell exactly when prices are worst. The Financial Times reported on 28 July that Goldman Sachs and JPMorgan were already telling concentrated funds to post additional collateral to maintain existing borrowing levels. A price decline that a cash investor would have read as a cheaper entry point reached Situational Awareness as a simultaneous demand for cash and a cut in the borrowing that financed the position. The mechanism matched Archegos in 2021, where margin-call default cost prime brokers around $10bn and earned Credit Suisse a record £87m fine from the Prudential Regulation Authority. The containment did not match. This book moved to one buyer overnight, and no bank losses have been reported.

The Hedge Was the Same Bet Twice

Borrowing four times capital was defensible only for a genuinely two-sided book, and this book was one-sided in substance. The long side held memory and neocloud exposure including SK Hynix, Micron, SanDisk, Nebius, CoreWeave and Bloom Energy. The short side held application software, including Adobe, on the view that AI tools would compress software margins. Both sides expressed the same underlying question about who captures AI value, and both moved against the fund in July. Marvell lost more than 30% over the period Bloomberg measured to mid-July, while Gizmodo reported Adobe up more than 30% over the month to 30 July. The Q1 2026 13F showed roughly $13.68bn of reported notional exposure, of which about $8.46bn sat in puts, which added time decay to an already time-sensitive structure.

What the Counterargument Gets Right

Borrowed money amplified an error that existed independently. Concentration in the most crowded, highest-beta corner of the market was a sizing decision, and an ungeared version of that book would still have suffered a severe drawdown. The fund also kept its private portfolio, including a stake in Anthropic, last valued at $965bn in a May Series H and expected to list within months, so cumulative returns since the 2024 launch are probably still strongly positive and the multi-year thesis may yet pay. The forced sale removed the liquid assets and left the illiquid ones, which inverts the risk profile the original structure assumed.

The transferable point is narrow. Conviction is priced in years, financing is priced overnight, and only one of those two contracts is enforceable. Allocators reading the next 400% half-year should ask what the fund's shortest liability is, because that number, rather than the pitch, defines how long a position can actually be held.

Sources

The unwind

  1. CNBC, "How Leopold Aschenbrenner built a $45 billion AI hedge fund — and lost most of it in days" https://www.cnbc.com/2026/07/31/leopold-aschenbrenner-situational-awareness-fund-fire-sale.html

  2. Reuters, "Citadel buys most of Situational's stock holdings after AI share rout, sources say" https://www.reuters.com/technology/citadel-buys-most-situationals-stock-holdings-after-ai-share-rout-sources-say-2026-07-30/

  3. Bloomberg, "Situational Awareness Assets Fall to $10 Billion After Losses" https://www.bloomberg.com/news/articles/2026-07-30/situational-awareness-assets-fall-to-10-billion-after-losses

  4. Business Insider, "Situational Awareness was forced to sell most of its stocks to Citadel. The fund got to keep its best asset." https://www.businessinsider.com/situational-awareness-keeps-anthropic-stake-portfolio-sale-citadel-2026-7

Market and financing conditions

  1. Bloomberg, "Chips Stocks Sink Into Bear Market as 105% AI Rally Fizzles" https://www.bloomberg.com/news/articles/2026-07-17/chips-stocks-tumble-into-bear-market-as-105-ai-rally-fizzles

  2. The New York Times, "Tech Stocks Tumble on Worries Over A.I. Spending and China's Chips" https://www.nytimes.com/2026/07/28/business/stocks-ai-chips.html

  3. Seoul Economic Daily (summarising the Financial Times), "Wall Street Issues Margin Calls to Hedge Funds as AI Stocks Tumble" https://en.sedaily.com/international/2026/07/29/wall-street-issues-margin-calls-to-hedge-funds-as-ai-stocks

  4. CNBC, "Chip stocks sell off after Samsung earnings fall short of high AI bar" https://www.cnbc.com/2026/07/07/chip-stocks-ai-selloff-samsung.html

Mechanism and precedent

  1. Markus Brunnermeier and Lasse Heje Pedersen, "Market Liquidity and Funding Liquidity" https://www.newyorkfed.org/medialibrary/media/newsevents/events/research/2006/0518-Mkt_Fun_Liquiditybrunnermeierandpedersen.pdf

  2. Bank of England Prudential Regulation Authority, "The PRA imposes record fine of £87m on Credit Suisse for serious risk management and governance failures in connection with Archegos Capital Management exposure" https://www.bankofengland.co.uk/news/2023/july/the-pra-imposes-record-fine-of-87m-on-credit-suisse