The OpenAI mafia: 15 of the most notable startups founded by alumni

Summary

Move over, PayPal mafia: There’s a new tech mafia in Silicon Valley. As the startup behind ChatGPT, OpenAI is arguably the biggest AI player in town. Its meteoric rise to a $300 billion valuation has spurred many employees to leave the AI giant to create startups of their own. The hype around OpenAI is so high that some of these startups, like Ilya Sutskever’s Safe Superintelligence and Mira Murati’s Thinking Machines Lab, have been able to raise billions of dollars without even launching a product. But there are lots of other startups in the OpenAI mafia ecosystem. These range from AI search giant Perplexity to xAI, the new owner of X (formerly Twitter.) There’s also smaller outfits with some futuristic plans, like Living Carbon, which is creating plants that suck more carbon out of the atmosphere, or Prosper Robotics, which is building a robot butler. Below is a roundup of the most notable startups founded by OpenAI alumni. Dario Amodei, Daniela Amodei, and John Schulman — Anthropic Siblings Dario and Daniela Amodei left OpenAI in 2021 to form their own startup, San Francisco-based Anthropic, that has long touted a focus on AI safety. Later, OpenAI co-founder John Schulman joined Anthropic in 2024, pledging to build a “safe AGI.” OpenAI reportedly remains multiple times larger than Anthropic by revenue ($3.7 billion compared to $1 billion for 2024, The Information reported). But Anthropic has quickly grown to become OpenAI’s biggest rival and was valued at $61.5 billion in March 2025. Ilya Sutskever — Safe Superintelligence OpenAI co-founder and chief scientist Ilya Sutskever left OpenAI in May 2024 after he was reportedly part of a failed effort to replace CEO Sam Altman. Shortly afterward, he co-founded Safe Superintelligence, or SSI, with “one goal and one product: a safe superintelligence,” he says. Details about what exactly the startup is up to are scant: It has no product and no revenue yet. But investors are clamoring for a piece anyway, and it’s been able...