Stealth chip startup Source Foundry has raised a fresh $400M at a $5B valuation, led by Leopold Aschenbrenner's Situational Awareness, taking the fund's total bet on the company to $500M.

The year-old startup, also backed by Sequoia, is redesigning the tooling and manufacturing steps that sit upstream of chip fabs to suit AI workloads. Its target: ASML, the Dutch giant whose extreme ultraviolet (EUV) lithography machines are essential for printing the world's most advanced AI chips.

The timing is striking. Aschenbrenner wired the $400M just days after his hedge fund reportedly lost nearly two-thirds of its assets, one of the year's most catastrophic blowups.