Microsoft’s early bet on OpenAI, which now seems prescient, was initially seen as a major risk, CEO Satya Nadella said.

The company invested $1 billion in OpenAI in 2019, less than four years after the startup was founded, and has since poured in more than $13 billion into the ChatGPT maker.

Speaking on the tech-focused YouTube show TPBN on Tuesday, Nadella said securing approval for that first investment wasn’t simple.

“Even at Microsoft, you kind of have to get board approval to just go throw a billion dollars out there,” he said. “But I must say it was not that hard to convince anyone that this is an important area and it’s going to be risky.”

Reflecting on the decision, Nadella added: “In retrospect, who would have thought? I didn’t put in a billion dollars saying, ‘Oh yeah, this is going to be a hundred bagger.’”

Bill Gates, he noted, had warned him the move could be like “setting $1 billion on fire.”