Amazon announced today it will invest an additional $4 billion in Anthropic, bringing its total investment to $8 billion. The deal solidifies AWS as Anthropic’s primary cloud and training partner, with Anthropic committing to use AWS’s custom Trainium and Inferentia chips to train and deploy its future foundation models.

The arrangement marks a deepening of ties first established last September. Anthropic will work closely with Annapurna Labs, AWS’s chipmaking division, to develop future generations of Trainium accelerators. AWS CEO Matt Garman framed the collaboration as a way to “push the boundaries of what customers can achieve with generative AI technologies.”

For Anthropic, the cash infusion—reported to be structured similarly to the previous $4 billion deal—comes as the startup projects burning through over $2.7 billion this year. The company has faced delays on its next-gen Claude 3.5 Opus model and an unexpected price hike on one of its models, but its Claude family has seen “breakout growth” in the past year, according to CEO Dario Amodei. The investment draws regulatory scrutiny from the FTC and the U.K.’s CMA, which has opened inquiries into big tech tie-ups with AI firms and already gave Amazon’s earlier deal the green light last year.