Why is SpaceX stock falling after-hours today?

SpaceX shares fell 2.9% in after-hours trading to $139.67 on Thursday, as a Bloomberg report, that Anthropic has become SpaceX’s single largest customer, raised fresh concerns about customer concentration risk, especially amid mounting concerns over a cooling AI trade.

Bloomberg reported that Anthropic was responsible for approximately 34.5% of SpaceX’s third-quarter revenue under a computing capacity contract worth up to $120.5 billion through 2029. While the deal itself was announced earlier in 2026 and initially cheered by the market, the specific revenue share figure, now confirmed, has prompted investors to question what a slowdown or disruption in Anthropic’s spending could mean for SpaceX’s top line, particularly as Anthropic’s own S-1 filing and pending IPO introduce a new layer of uncertainty about the customer relationship.

Compounding the pressure, the Louisiana spaceport lawsuit continues to linger as a secondary headwind. A nonprofit and three Vermilion Parish residents have filed suit alleging eight violations of Louisiana’s Open Meetings Law in connection with the tax incentive framework underpinning SpaceX’s planned $100 billion Starbase Louisiana development, putting a $25 million annual payment-in-lieu-of-taxes agreement at legal risk.

Separately, the stock has been drifting back toward the $140 technical support level that has held since summer, still weighed down by supply overhang from the October 22 unlock of up to 1.3 billion shares, while fourth-quarter capital expenditure guidance of $35–$40 billion continues to raise free cash flow concerns.

The broader market offered no relief today. The Nasdaq dropped 1.7% as tech stocks broadly sold off, and the S&P 500 slipped 0.7%, with the interest rate outlook turning more hawkish after a Q3 GDP reading of 3.4% exceeded analyst forecasts and reinforced expectations of a Federal Reserve rate hike in December. High-valuation growth names like SPCX are particularly sensitive to rising rate expectations.