OpenAI

OpenAI is an American artificial intelligence (AI) public benefit corporation (PBC) headquartered in San Francisco, California. It develops proprietary generative AI models, particularly its generative pre-trained transformer (GPT) series of large language models. Its release of ChatGPT in November 2022 has been credited with catalyzing the AI boom; as of September 2026, ChatGPT is the fifth-most-visited website globally. OpenAI also releases the GPT Image models and Codex, an AI coding agent. In March 2026, OpenAI closed a funding round with a post-money valuation of US$852 billion, making it one of the most valuable AI pure play companies in the world, rivalled only by Anthropic. OpenAI was founded in 2015 as a nonprofit, with Elon Musk and Sam Altman as co-chairs; Musk resigned in 2018. A for-profit subsidiary was created in 2019, and a 2025 restructuring converted the subsidiary into OpenAI Group PBC, that is 26% owned by the nonprofit OpenAI Foundation. Microsoft has invested over $13 billion into OpenAI. OpenAI partners with the US government via the Stargate Project infrastructure venture, and with the Department of Defense, Los Alamos National Laboratory, and arms company Anduril Industries. Former OpenAI personnel have founded competing AI companies including Anthropic, Safe Superintelligence Inc., SpaceXAI, and Thinking Machines Lab. OpenAI has faced multiple lawsuits for alleged deaths linked to its chatbots and copyright infringement against authors and media companies. In November 2023, OpenAI's board removed Sam Altman as CEO, citing a lack of confidence, but reinstated him five days later after a board reconstruction. In 2024, roughly half of OpenAI's AI safety researchers left the company, often citing the company's deprioritization of safety. Between May and July 2026, OpenAI agents gained unintended internet access and conducted a series of autonomous cyberattacks. In September, OpenAI claimed a proof regarding Navier–Stokes existence and smoothness, a Millennium Prize...