OpenAI has closed the largest venture capital round in history, securing $6.6 billion at a $157 billion post-money valuation. The round was led by Thrive Capital, which invested approximately $1.3 billion, with an option to inject up to $1 billion more through 2025. Microsoft invested just under $1 billion, SoftBank contributed $500 million, Nvidia put in $100 million, and participants also included MGX, Khosla Ventures, Altimeter Capital, and Fidelity. The total raised by OpenAI now stands at $17.9 billion.

The terms come with unusual conditions. According to Bloomberg, investors can claw back their cash if OpenAI fails to transition from its nonprofit governance to a for-profit structure within two years. Reports from the Financial Times indicate OpenAI asked investors to avoid funding rival startups like Anthropic and xAI. The company is burning through billions: The Information reports roughly $7 billion on model training and $1.5 billion on staffing. ChatGPT costs an estimated $700,000 per day to run.

OpenAI noted the funds will be used to “double down on our leadership in frontier AI research, increase compute capacity, and continue building tools that help people solve hard problems.” This comes amid an executive exodus: CTO Mira Murati, chief research officer Bob McGrew, and research VP Barret Zoph resigned in late September. Of the 13 original founders, only three remain.