So here's the thing about building an AI company to take on Google and OpenAI: sometimes the people who helped you start it decide they'd rather not stick around for the IPO. Late Thursday, Toby Pohlen, one of the co-founders of Elon Musk's xAI, took to X (the platform, not the company) to announce he's leaving after three years.

"Three years, thousands of PRs, and a million jokes…." Pohlen wrote in his farewell note, adding some gratitude for his team and for Musk himself. "I've learnt more about execution, speed, and product perfectionism than I could ever have imagined," he said. His post suggested he'll be taking some time off to rest, document his experiences, and figure out what's next.

Musk, being Musk, kept his response brief: "Thanks for helping get xAI to where it is." Which is… where exactly? That's where things get interesting.

The Great xAI Exodus

Pohlen isn't just leaving—he's joining what's starting to look like a parade out the door. Earlier this month, the company lost two other co-founders, Yuhuai "Tony" Wu and Jimmy Ba. And they were following earlier exits from the founding team: Christian Szegedy left last February, Igor Babuschkin departed in August, and Greg Yang recently stepped down due to health reasons.

Do the math: that's half of the original founding team gone. For a company that was founded in 2023 specifically to challenge Alphabet Inc.'s (GOOG) Google and OpenAI in the AI race, that's… not ideal timing. Especially when you're reportedly preparing for a potential IPO.

Musk's Restructuring Play

So what's Musk doing about all this? Restructuring, of course. Following the wave of departures, he announced a reorganization of xAI, saying it was necessary to improve execution speed and, unfortunately, required parting ways with some people. "We are hiring aggressively," he added, which is the corporate equivalent of "we're breaking some eggs to make this omelet."

The timing of this shake-up is particularly noteworthy because it comes after SpaceX acquired xAI in an all-stock deal that valued SpaceX at $1 trillion and xAI at $250 billion. Yes, you read that right—a quarter of a trillion dollars for a company that's losing half its founding team. xAI, which owns social media platform X and develops the Grok AI chatbot and image generator, was previously used by Musk in another all-stock acquisition of X.

Think about that for a second: Musk used xAI to buy X, then SpaceX bought xAI, and now xAI is restructuring while preparing for an IPO. It's like corporate Russian nesting dolls, but with more billion-dollar valuations and departing co-founders.

The real question isn't just who's leaving, but why now? When you're gearing up for a public offering, you typically want to show stability, not a revolving door of key personnel. But maybe that's the point—maybe Musk believes he needs a different team to execute at the speed required to compete in the AI arms race. Or maybe founding an AI company is just really hard work, and after three years of "product perfectionism," some people need a break.

Either way, xAI's brain drain is becoming impossible to ignore. When half your founding team leaves in the year before a potential IPO, investors tend to notice. They'll be watching closely to see who Musk hires to replace them—and whether the new team can deliver on that $250 billion valuation.