OpenAI
Also known as: OpenAI Group PBC
OpenAI was founded in 2015 as a nonprofit AI research lab by Sam Altman, Elon Musk, Greg Brockman, and others. It later restructured into a capped-profit model to attract the capital needed to train frontier models, and in October 2025 completed a further restructuring into a hybrid model where the nonprofit foundation holds a stake in the for-profit operating company. Microsoft is OpenAI's largest strategic investor, holding roughly 27% equity following cumulative investments exceeding $13 billion.
The company's public trajectory changed dramatically with the November 2022 launch of ChatGPT, which became the fastest consumer software product to reach 100 million users. By early 2026, OpenAI was generating approximately $2 billion per month in revenue at a $20+ billion annualized run rate, with ChatGPT surpassing 900 million weekly active users and 50 million paying subscribers. Enterprise now accounts for more than 40% of revenue. The company closed a $122 billion funding round at an $852 billion valuation in March 2026.
For builders, OpenAI matters through several surfaces: the ChatGPT product itself, the OpenAI API and Responses API for developers, the Codex coding agent, and specialized tools like Sora for video generation. The current flagship model family is GPT-5.x, with GPT-5.5 the most capable model as of May 2026. OpenAI has been moving toward what it calls a 'unified AI superapp' that brings together ChatGPT, Codex, browsing, and agentic capabilities into a single agent-first product surface.