Eight months after Erik Kriessmann (@ekriessmann) led @Castelion's Series B, Altimeter is pumped to deepen our commitment and continue our partnership with Bryon (@hargsb), Sean, Andrew, and the entire Castelion team as they announce their $1B Series C at a $13B valuation. Castelion is building with a rare combination of speed, technical ambition, and manufacturing scale. In just a few years, the team has taken Blackbeard from a clean-sheet design to flight-tested hardware and a program of record, secured more than $500M in U.S. military contracts, and has begun building what is currently the largest dedicated hypersonic missile manufacturing facility in the country. We believe Castelion is building one of the most important defense companies of this generation and demonstrating what is possible when American engineering and manufacturing move with urgency. Designed in California. Built in New Mexico. Supplied by businesses across America.

Noam Brown (@polynoamial) posted something profound this week. Frontier models can solve most problems if you just let them run long enough. Nobody has ever run Mythos for a full year. We may never know how smart any given generation actually is. @GavinSBaker's takeaway: however bullish he was on compute before that post, he's more bullish now. @altcap