OpenAI is the San Francisco lab behind ChatGPT and, for this directory, the agents built on its frontier models — most notably Codex, its software-engineering agent, alongside computer-using agents that operate a browser and desktop on a user’s behalf. Founded in late 2015 as a nonprofit “to ensure that artificial general intelligence benefits all of humanity,” it has since restructured toward a for-profit model under CEO Sam Altman.

ChatGPT’s launch in late 2022 made OpenAI one of the fastest-growing companies in history, and its annual run-rate revenue passed $20B by the end of 2025. That reach doubles as a distribution channel: developers build on its APIs, and its agent products push beyond chat toward systems that carry out multi-step work on their own.

The funding is the largest in private-company history. After a SoftBank-led $40B round in 2025, OpenAI closed roughly $122B at an $852B post-money valuation in March 2026 — backed by SoftBank, Amazon, Nvidia and Microsoft — and filed confidentially for a US IPO on June 8, 2026, with reporting pointing to a listing as late as 2027. Microsoft remains its longest-standing strategic partner and cloud provider.