Fab2 Raises $500M Series A to Mass-Produce Chip Fabs
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Fab2, the semiconductor startup formerly known as Atomic Semi, has raised a $500 million Series A at a $3.7 billion valuation. The round, led by Fundomo, was reported on September 9, 2026.
Corner Capital, Paradigm, Duquesne Family Office, Maverick Silicon, StepStone Group, Protagonist, UDC Ventures, and angel investor Naval Ravikant also took part in the Series A. The company previously raised a $15 million seed led by the OpenAI Startup Fund in 2023 at a valuation of roughly $100 million, which means its valuation has climbed close to 37 times in under three years. The round ranks in the 99th percentile of all US Series A deals on record.
Fab2 renamed itself in July and moved its headquarters to Austin, Texas, where a 120,000 square foot facility now houses research and production. A 30,000 square foot site in Lockhart, Texas holds the company’s fab-making operation, and the original 25,000 square foot facility remains in San Francisco. The company shifted its hiring focus to Texas after four years in California.
The premise is a factory that builds factories. Fab2 designs and manufactures every piece of equipment that goes inside a chip fab, from pumps, valves, and gas lines to lithography tools and vacuum chambers, then assembles those tools into compact fabs it intends to produce at scale. The process is automated in software so new manufacturing recipes can be tested quickly. The company’s slogan is that it prints chips.
Founded in 2022, Fab2 is led by co-founder and CEO Sam Zeloof, who became known for fabricating chips in his family’s garage as a high school student. Co-founder Jim Keller is the veteran chip designer behind AMD’s Zen, Apple’s A4 and A5, and Tesla’s Autopilot chip, and he also runs the AI chipmaker Tenstorrent.
The funding lands as the United States pushes to bring chip supply chains home. Building a single conventional fab typically costs billions of dollars and takes years, which has left advanced foundry work to a small group of companies such as TSMC, Samsung, and Intel, with ASML dominating lithography equipment. Startups attacking that equipment stack are drawing large rounds: Substrate raised a $100 million seed above a $1 billion valuation for a particle-accelerator lithography approach, xLight is developing EUV light sources, and Source Foundry has drawn $500 million at a $5 billion valuation before shipping a product.
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