Mark Chen, the chief research officer at OpenAI, sent a forceful memo to staff on Saturday, promising to go head-to-head with the social giant in the war for top research talent. This memo, which was sent to OpenAI employees in Slack and obtained by WIRED, came days after Meta CEO Mark Zuckerberg successfully recruited four senior researchers from the company to join Meta’s superintelligence lab.

“I feel a visceral feeling right now, as if someone has broken into our home and stolen something,” Chen wrote. “Please trust that we haven’t been sitting idly by.”

Chen promised that he was working with Sam Altman, the CEO of OpenAI, and other leaders at the company “around the clock to talk to those with offers,” adding, “we’ve been more proactive than ever before, we’re recalibrating comp, and we’re scoping out creative ways to recognize and reward top talent.”

Still, even as OpenAI leadership appears desperate to retain its staff, Chen said that he has “high personal standards of fairness,” and wants to retain top talent with that in mind. “While I’ll fight to keep every one of you, I won’t do so at the price of fairness to others,” he wrote.

The news comes as competition for top AI researchers is heating up in Silicon Valley. Zuckerberg has been particularly aggressive in his approach, offering $100 million signing bonuses to some OpenAI staffers, according to comments Altman made on a podcast with his brother, Jack Altman. Multiple sources at OpenAI with direct knowledge of the offers confirmed the number. The Meta CEO has also been personally reaching out to potential recruits, according to the Wall Street Journal. “Over the past month, Meta has been aggressively building out their new AI effort, and has repeatedly (and mostly unsuccessfully) tried to recruit some of our strongest talent with comp-focused packages,” Chen wrote on Slack.

A source close to the efforts at Meta confirmed the company has been significantly ramping up its research recruiting, with a particular eye toward talent from OpenAI and Google. Anthropic, while also a top rival, is thought to be less of a culture fit at Meta, one source tells WIRED. “They haven’t necessarily expanded the band, but for top talent, the sky is the limit,” the source says.

Both OpenAI and Meta did not respond to requests for comment.

Chen’s note included messages from seven other research leaders at the company, where they wrote notes to staffers in an apparent effort to encourage them to stay. One leader on the research team encouraged staff to reach out if they received an offer from Meta: “If they pressure you, or make ridiculous exploding offers just tell them to back off, it’s not nice to pressure people in potentially the most important decision. WIRED is not naming the leader as they are not a C-suite executive. “I’d like to be able to talk to you through it and I know all about their offers.”