OpenAI has told employees it has finalized a tender offer that allowed some staff to cash out their holdings, one person with direct knowledge of the situation said. The move caps a process that began last fall alongside talks to raise billions of dollars from Microsoft.

Over the past few months, the San Francisco startup behind artificial intelligence–powered chatbot ChatGPT has negotiated the tender offer in which investors buy employee profit units—essentially, rights to future OpenAI profits—at a price that implies a roughly $27 billion valuation, two people with direct knowledge of the discussions said. The size of the deal couldn’t be learned.

The sale rewards some of the eight-year-old firm’s 400 employees as recent advances in generative AI—technology that uses large machine-learning models to create humanlike writing, images and codes—heightens demand for these specialized employees.