Liam Fedus
Liam Fedus (William Fedus) is an artificial intelligence researcher and entrepreneur who served as OpenAI’s vice president of research in charge of post-training, and in 2025 co-founded Periodic Labs with Ekin Dogus CubukEkin Dogus CubukPeriodic Labs cofounder and co-CEO, working at the intersection of machine learning and physics.Open the full entry to accelerate scientific discovery with AI.
Contents8 sections
Key facts
January 2021Publishing the Switch Transformers Paper
In January 2021, he submitted the paper “Switch Transformers” to arXiv as first author with Barret Zoph and Noam Shazeer, proposing a simplified sparse mixture-of-experts (MoE) routing approach for scaling language models to trillion-parameter size.[1]
2022Joining OpenAI
According to Maginative, he joined OpenAI in 2022 after leaving Google. A deal announcement by the law firm Wilson SonsiniWilson Sonsini Goodrich & RosatiWilson Sonsini Goodrich & Rosati (known as Wilson Sonsini) is a law firm headquartered in Palo Alto, California, founded in 1961 and known for serving technology, life sciences, and other growth companies and their investors; it served as counsel on the initial public offerings of companies including Apple, Netscape, Google, and Tesla. As of December 2025 the firm had more than 1,000 lawyers, and its 2025 revenue was $1.4 billion.Open the full entry describes him as one of the co-creators of ChatGPT.[2][3]
Fall 2024: Promoted to Vice President of Research at OpenAI
The same report says he was promoted to vice president of research in fall 2024, heading post-training, the stage in which models are refined after their initial training.[2]
March 2025Announcing His Departure from OpenAI to Start a Company
In March 2025, he announced that he was leaving OpenAI to start a company applying artificial intelligence to materials science. In a post on X he said his undergraduate degree was in physics and that OpenAI planned to invest in and partner with the new company; OpenAI also confirmed his departure to the media.[2]
September 30, 2025Periodic Labs Launches with a $300 Million Seed Round
On September 30, 2025, Periodic Labs, which he co-founded with Ekin Dogus Cubuk, who had led the materials and chemistry team at Google Brain and DeepMindGoogle DeepMindGoogle DeepMind is Google’s artificial intelligence research organization, formed in April 2023 by merging DeepMind, which Google acquired in 2014, with the Brain team from Google Research, and led by CEO Demis Hassabis. It developed AlphaGo, AlphaFold, and the Gemini family of models, and Hassabis and John Jumper received the 2024 Nobel Prize in Chemistry for AlphaFold’s protein structure prediction work.Open the full entry, announced a $300 million seed round led by Andreessen HorowitzAndreessen HorowitzAndreessen Horowitz (a16z) is a venture capital firm founded in 2009 by Marc Andreessen and Ben Horowitz. It invests from the seed stage through the growth stage and provides operational support to its portfolio companies.Open the full entry, with participants including Felicis, DST GlobalDST GlobalDST Global is a technology investment firm founded by Yuri Milner in 2009 that focuses on growth-stage investments in internet companies worldwide; it has invested in companies including Facebook, Twitter, Alibaba, JD.com, Airbnb and Spotify, and in 2026 led the US$400 million Series B round of the AI visual content company Higgsfield.Open the full entry, NVIDIA and Accel.[3][4]
According to reports, the company plans to build closed-loop, self-driving laboratories in which AI agents propose hypotheses and run experiments, with an initial focus on finding superconductors that work at higher temperatures.[4]
As of October 2026: Co-CEO of Periodic Labs
Related Organizations, Websites, and Public Accounts
OpenAI: Official website: https://openai.com/ (opens in a new window)[2]
Periodic Labs: Official website: https://periodic.com/ (opens in a new window)[6]
X: Public account: https://x.com/LiamFedus (opens in a new window)[2]
Sources
- Switch Transformers: Scaling to Trillion Parameter Models with Simple and Efficient Sparsity (opens in a new window)
- OpenAI’s Post-Training Head Liam Fedus Departs to Launch AI-Powered Materials Science Startup (opens in a new window)
- Wilson Sonsini Advises Periodic Labs on $300 Million Seed Round (opens in a new window)
- Periodic Labs launches with $300M to build an “AI scientist” (opens in a new window)
- William (Liam) Fedus (opens in a new window)
- Periodic Labs (opens in a new window)