Why is SpaceX stock falling after-hours today?

In after-hours trading on Thursday, SpaceX shares fell by 2.9% to $139.67, as a Bloomberg report about Anthropic becoming the company's largest customer raised fresh concerns about customer concentration risk. The report revealed that Anthropic accounts for approximately 34.5% of SpaceX's third-quarter revenue under a contract worth up to $120.5 billion through 2029.

While the deal was announced and well-received earlier in 2026, the specific revenue share figure has now prompted investors to question the potential impact of a slowdown or disruption in Anthropic's spending on SpaceX's top line. Anthropic's pending IPO adds to the uncertainty surrounding the customer relationship. In addition to the customer concentration concerns, SpaceX faces a potential legal risk from a lawsuit filed by a nonprofit and three Vermilion Parish residents over alleged violations of Louisiana's Open Meetings Law in connection with the tax incentive framework for the Starbase Louisiana project.

This $25 million annual payment-in-lieu-of-taxes agreement is at risk due to the legal challenges. The stock has also been drifting back toward the $140 technical support level, weighed down by supply overhang from an October 22 share unlock and fourth-quarter capital expenditure guidance of $35–$40 billion, which raises concerns about free cash flow.

The broader market offered no relief, with the Nasdaq dropping 1.7% as tech stocks sold off, and the S&P 500 slipping 0.7%. A more hawkish outlook on interest rates was reinforced after the Q3 GDP reading of 3.4% exceeded analyst forecasts, further impacting high-valuation growth names such as SPCX.