Shares of Palantir plunged 6.6% on a day the S&P 500 gained 2.5%, after famed "Big Short" investor Michael Burry publicly attacked the company's competitive position — then quietly deleted the posts. The sell-off hit after Burry argued on X that Anthropic is "eating Palantir's lunch" in enterprise AI, calling the stock a potential bubble. The stock clawed back slightly in after-hours but closed at $131.96, leaving investors to decide whether the damage was a one-day scare or a preview of deeper trouble.
The Man Who Shorted the Housing Market Now Has $912 Million Riding Against Palantir. Burry previously disclosed a sizeable short via long-dated $50 strike put options expiring in 2027, giving him downside exposure to roughly 5 million shares.
Since his bearish campaign began in early November, the stock is down 26%. He deleted his latest posts, but the data he cited hasn't disappeared — and that's what matters to institutional holders.
Anthropic's Revenue Growth Makes Palantir's Numbers Look Tiny. Burry noted Anthropic went from $9 billion to $30 billion in annualized revenue in months; it took Palantir 20 years to reach $5 billion.
Ramp's March AI Index shows business AI adoption at a record 47.6%, with nearly one in four Ramp customers now paying for Anthropic — up from roughly one in 25 a year ago.
Burry highlighted that 73% of emerging enterprise AI spending is flowing toward Anthropic. Even if those figures overstate the threat — Anthropic builds AI models while Palantir integrates them — the speed of that shift rattles investors.
A 115x Forward Price-to-Earnings Ratio Leaves Zero Room for Error. At a forward P/E of around 115x, Palantir trades well above its sector median of 21x and far above other large-cap AI names.
Even at 78 times sales, Palantir is still the most expensive stock in the S&P 500 by a wide margin. That premium demands flawless execution. Q4 2025 revenue hit $1.4 billion — up 70% year-over-year — and full-year net income surged 252% to $1.6 billion. But growth alone doesn't justify the multiple if rivals sell a cheaper, simpler product directly to the same corporate buyers.
The Defense Cushion Is Thinning Too. A recent ceasefire has unwound the "war premium" that previously boosted Palantir's stock, leading to decreased expectations for defense-related revenue.
Insiders sold $292 million worth of shares in March alone, with Peter Thiel accounting for over 98% of that.
Burry's posts may be gone, but his thesis — that a cheaper AI rival is vacuuming up corporate budgets while Palantir trades at a nosebleed valuation — remains squarely on the table.