Castelion raises $800M Series C at $13B

The $800M is equity only. Castelion also secured a $250M revolving credit facility, so the package was announced as a $1B Series C on August 19, 2026. A credit line is borrowing capacity rather than cash, and the $13B valuation applies to the equity. JPMorgan's Strategic Investment Group, a16z and Carlyle co-led. Lightspeed, Lavrock, Altimeter, General Catalyst, Interlagos and new investor T. Rowe Price also took part.

Proceeds go toward mass production of Blackbeard, a low-cost hypersonic strike missile the company aims to field in 2027. Castelion was founded in 2023 by former SpaceX engineers and is based in Torrance, California. Its Series B closed in December 2025 and raised $350M, led by Altimeter and Lightspeed. Axios ties the demand to stockpiles depleted by the wars in Iran and Ukraine. Castelion competes for capital with other defense startups, including Anduril, which was reported at $61B in the same news cycle.

For AI founders, the round shows crossover investors and bank balance sheets paying for hardware that scales through manufacturing and government contracts, not software margins. Capital for defense-adjacent AI, autonomy and compute is getting more competitive. Founders in that space should expect investors to benchmark them against these valuations. They should also expect questions about production capacity and contract backlog.