OpenAI was announced in December 2015 as a nonprofit artificial intelligence research lab and later added a capped-profit arm that drew billions of dollars from Microsoft and other investors. After the launch of ChatGPT in 2022 it raised funding at valuations of hundreds of billions of dollars. In October 2025 it completed a recapitalization under which the nonprofit OpenAI Foundation controls a for-profit public benefit corporation.
OpenAI Group PBC is a private company controlled by the OpenAI Foundation, with Sam Altman as chief executive. A jury rejected Elon Musk's claims as time-barred in May 2026. Musk said he would appeal to the Ninth Circuit, and no appellate ruling has been reported.
OpenAI announced itself as a nonprofit artificial intelligence research company, with Sam Altman and Elon Musk as co-chairs. The announcement said backers had committed $1 billion.
OpenAI said it had created OpenAI LP, a capped-profit company controlled by the nonprofit. Returns for first-round investors were capped at 100 times their investment and the announcement listed Sam Altman as CEO.
OpenAI announced that Microsoft would invest $1 billion and become its exclusive cloud provider.
OpenAI released an API giving developers access to its AI models. The company said developing commercial products was one way to fund its mission.
OpenAI released ChatGPT as a research preview that was free to use during the preview.
Microsoft announced a multiyear, multibillion dollar investment extending its partnership with OpenAI. It did not disclose the amount.
OpenAI announced GPT-4, which it called a large multimodal model. It was made available to ChatGPT Plus subscribers and to developers through an API waitlist.
Italy's data protection authority, the Garante, ordered an immediate temporary limitation on OpenAI's processing of data of users in Italy. In its announcement it cited the lack of a legal basis for mass collection of personal data to train the algorithms and the absence of age verification.
OpenAI's board announced that Altman would depart as CEO and leave the board after a review. It named chief technology officer Mira Murati interim CEO.
OpenAI announced that Altman had returned as CEO. The new initial board was Bret Taylor as chair, Larry Summers and Adam D'Angelo, with a non-voting observer seat for Microsoft.
The New York Times Company sued Microsoft and OpenAI in the US District Court for the Southern District of New York. Its complaint alleged that the companies copied its journalism without permission to build their AI products.
OpenAI said a review by law firm WilmerHale found a breakdown in trust between the prior board and Altman, and that his conduct did not mandate removal. Altman rejoined the board and three new directors were named.
OpenAI said it had raised $6.6 billion in new funding at a $157 billion post-money valuation.
The Garante announced it had closed its ChatGPT investigation, fining OpenAI 15 million euros and ordering a six-month public information campaign. The underlying decision, number 755, was dated 2 November 2024.
OpenAI announced the Stargate Project, naming SoftBank, OpenAI, Oracle and MGX as initial equity funders. It said the venture intended to invest $500 billion in US AI infrastructure over four years.
OpenAI announced $40 billion in new funding at a $300 billion post-money valuation, in partnership with SoftBank Group.
OpenAI said its nonprofit would continue to control the company and that the for-profit arm would become a public benefit corporation.
OpenAI announced it would merge with io, the hardware start-up co-founded by designer Jony Ive. It did not state a price in its announcement.
OpenAI released GPT-5 and made it the default model in ChatGPT.
OpenAI said the nonprofit, renamed the OpenAI Foundation, keeps control of the business, now OpenAI Group PBC. It said the Foundation's equity stake was valued at about $130 billion.
Microsoft said it held about 27 percent of OpenAI Group PBC, valued at about $135 billion, and that OpenAI had contracted to buy an incremental $250 billion of Azure services.
The Tribunale di Roma upheld OpenAI's challenge and annulled the Garante decision that imposed the 15 million euro fine and the information campaign. The court accepted the argument that the Garante lacked competence and did not rule on the other grounds.
Bloomberg Law reported that OpenAI had completed a $122 billion funding round at an $852 billion valuation, with Amazon, Nvidia and SoftBank as the largest investors. Part of the Amazon investment was reported to be conditional.
A unanimous jury in the US District Court in Oakland found that Musk had filed his claims too late under the statute of limitations. Judge Yvonne Gonzalez Rogers said there was substantial evidence to support the finding. Musk said he would appeal to the Ninth Circuit.
International Business Times reported that Musk's company xAI had appealed to the Ninth Circuit after its trade secrets suit against OpenAI was dismissed in the lower court. It reported that Musk had said he would appeal the May verdict but did not report a filing.
OpenAI said ChatGPT Ads had reached $1 billion in annualized revenue run rate and was expanding globally.
OpenAI introduced GPT-6 Astra, which it described as its most intelligent and aligned model yet.
OpenAI said AI alignment researcher Paul Christiano had joined the OpenAI Foundation board and its Safety and Security Committee.
OpenAI said GPT-6 was rolling out globally in ChatGPT together with a feature it calls Intelligent UI.
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Last updated 31 October 2026. Spotted an error? See corrections. Every event links to the record it comes from. Allegations are attributed to whoever made them.