Speaking on his brother Jack's podcast, Sam Altman said he respected Meta's aggression in competing with OpenAI, which makes the world's best known AI-powered product, ChatGPT.
He said in addition to the signing bonuses, Meta was offering more than that in "compensation per year", though did not spell out whether that was in wages or stock options and other incentives.
But Mr Altman said he thought people were staying at OpenAI because of its "really special culture" and "mission" of creating superintelligence and the "economic awards and everything else flowing from that".
OpenAI and other AI firms think artificial general intelligence (AGI) is not far off, which would mean AI systems can perform as well as - or better than - humans.
Superintelligence is the next step, where the aim is to create AI which can vastly outperform human cognitive abilities.
"There's many things I respect about Meta as a company, but I don't think they're a company that's, like, great at innovation," Mr Altman told his brother.
Big tech firms are spending vast amounts of money researching and developing AI.
For example, in January OpenAI announced a joint deal with other funders to spend $500bn on a number of new data centres - which power AI - in the US.
