Michael Burry rebuilt his bet against artificial intelligence over a single weekend. In the newsletter published on Monday, September 28 on his Substack, Cassandra Unchained, the investor made famous by The Big Short wrote that put options have now replaced every short position: "As of today, put options completely replaced my short positions." It is not a change of thesis but of instrument and horizon: puts are cheap while volatility sits near its lows, and they buy far more leverage over a shorter window.
The reshuffle covered the whole bearish book. Burry closed his shorts in Micron, Nebius, Caterpillar, the iShares Semiconductor ETF (SOXX), CoreWeave, Nvidia, Palantir and Oracle, replacing them with put options; on CoreWeave the stock position has been covered but the puts have not been bought yet at a price he considers attractive. The post also discloses one new bearish position, in MetLife, built with long-dated puts expiring several years out and strikes in the $70s.
The expiries carry the most information. The Micron puts expire in June with strikes around $500; the Nebius puts also expire in June, with double-digit strikes. Caterpillar was moved into December 2027 puts struck around $400, while the SOXX short was replaced with September 2027 puts struck in the low $400s. On Nvidia the strike sits in the mid $100s for September 2027, and the Palantir position has been enlarged and concentrated on the same September 2027 expiry, with strikes in the low $100s.
Oracle moved to December 2027 puts with mid-double-digit strikes, while the QQQ put position was folded into a larger exposure rolled onto the Nasdaq 100, with strikes in the $24,000s for September 2027. The motive, Burry wrote, is only partly fiscal: tax-loss harvesting played a role, but "the majority" of the repositioning came from weekend research. "Fundamentally, I am moving timelines up," he added: with clearer timelines leverage becomes more palatable, and puts stay relatively cheap because volatility gauges such as the VIX remain exceptionally tight.
Behind the trades sits the Ares Management report Burry cited in the newsletter: the AI boom rests on capital spending that is assumed to continue and on revenue that is still unproven. "It would take only a season in which AI revenue disappoints the capital expenditure underwriting it," the report reads, because a handful of boards would then need only to conclude that the highest-conviction bet has shifted, a decision the legal documents already contemplate. Until recently Burry's base case was 2028: in August he named that year as the horizon for the bubble to burst, warning that large market cycles can take months or years to unwind. The June 2027 expiry on the Micron and Nebius puts now becomes the first test of the shortened calendar.
The market has not proved him right so far. The Nasdaq Composite closed at a record last week, Micron trades about 16% below its own record and Palantir roughly 10% below its all-time high. Year to date Micron is up more than 276% and Nebius 175%, while Nvidia has gained 22% and Palantir a more modest 0.34%. Burry has argued for months that the picture echoes the last months of the 1999-2000 bubble, and he cites Acer chief executive Jason Chen, who said a continuous memory shortage cannot last with Chinese production capacity still growing.
So the question is not whether Micron's or Palantir's numbers are real today, because they are, but whether the price already discounts a shortage and a spending wave built to last. Moving the bet from shares into puts changes the nature of the claim: no longer a valuation judgement without an end date, but a precise window in which the cycle has to turn, June 2027 for memory and September 2027 for software and semiconductors. If options leverage is the answer to low volatility, the risk is symmetrical and dated: the premium decays with time, and every quarter of confirmed capital spending pushes the position further against the bears.
Sources
- CNBC - Michael Burry believes the AI bubble 'may burst' sooner than he first believed (28/09/2026): cnbc.com
- Yahoo Finance / Stocktwits - Michael Burry Swaps MU, NBIS, NVDA, PLTR Shorts For Puts (28/09/2026): finance.yahoo.com
- Yahoo Finance / BeInCrypto - Michael Burry Said AI Bursts in 2028. One Weekend of Research Changed That (29/09/2026): finance.yahoo.com
- Yahoo Finance / MT Newswires - Burry Sees AI Bubble Bursting Sooner, Shifts to Put Options (29/09/2026): finance.yahoo.com
