Andrew Tulloch, a computer scientist and machine learning expert from Australia, may not be a widely recognized name, but he is now known as “the man who turned down a billion-dollar offer from Mark Zuckerberg.” Tulloch, currently working at the artificial intelligence startup Thinking Machine Lab founded by former OpenAI executive Mira Murati, drew international headlines this week after it was reported that he rejected a highly lucrative offer from the Meta CEO and remained loyal to the company where he is considered one of the founders.

According to reports, Zuckerberg personally approached Tulloch with an offer of a six-year contract valued at up to one point five billion dollars, based on bonuses and stock performance.

Tulloch had also previously turned down OpenAI.

In 2016, company president Greg Brockman attempted to recruit him as one of its first employees, writing to Elon Musk, then an investor in the company, that Tulloch would likely demand a higher salary than what he was earning at Facebook, which at the time stood at eight hundred thousand dollars per year.

However, OpenAI’s offer was one hundred seventy-five thousand dollars plus a one hundred twenty-five thousand dollar annual bonus.

“Andrew is very close to agreeing, but he is worried about the sharp drop in salary,” Brockman wrote.

Tulloch ultimately stayed at Facebook for another seven years.

In February this year, Tulloch left OpenAI and joined Murati in establishing a new AI startup.

The company employs about fifty people, more than twenty of whom came with her from OpenAI.

Few details are known about their product, but the company’s mission statement declares it is developing “AI systems that will be more broadly understandable, customizable, and with more general capabilities.” Murati recently said the firm is “building multimodal AI that works with the way you naturally interact with the world,” and that its first product would be revealed “in the next two months.” Despite its limited track record and recent founding, the company has already raised capital at a valuation of twelve billion dollars.

Although until recently Tulloch was not well known globally, he had established a reputation in AI and technology circles as a mathematical genius, a factor that may explain Zuckerberg’s high offer.

Tulloch grew up in Perth, Australia, and graduated with distinction in mathematics from the University of Sydney, where he won awards and held the highest grade average in his class.

He later earned a master’s degree at Cambridge and completed his doctorate at Berkeley.

Despite the high-profile rejection, Tulloch had in fact worked at Meta, then still called Facebook, for eleven years between 2012 and 2023.

He was part of the machine learning systems development team and contributed to the creation of PyTorch, one of the most widely used libraries in artificial intelligence.

“He was definitely known in the company as a super-genius,” said Mike Vernal, one of his former supervisors.

In 2023 he joined OpenAI, where he focused on training the GPT-4 model.