Fab2 Raises $500 Million Series A at a $3.7 Billion Valuation
Startups / news
Fab2 Raises $500 Million Series A at a $3.7 Billion Valuation
Jim Keller and Sam Zeloof's chip-factory startup priced 37 times above its 2023 seed round, even as building permits show a smaller Austin footprint than the company has described.
Fab2, the semiconductor startup that designs and mass-produces small chip fabrication plants, raised $500 million in a Series A round at a $3.7 billion valuation, Crunchbase News reported this week, ranking it among the ten largest rounds of Sept. 5 to 11.
Fundomo led the round. Corner Capital, Duquesne Family Office, Maverick Silicon, StepStone Group, Protagonist, UDC Ventures and angel investor Naval Ravikant also participated, according to Fab2's own site, which lists the full investor roster alongside its three-city footprint.
A 37-times jump from the seed round
Fab2 was founded in 2022 as Atomic Semi and raised a $15 million seed round in 2023, led by the OpenAI Startup Fund, at a valuation of roughly $100 million. The new $3.7 billion price is about 37 times that mark, reached across three years in which the company renamed itself Fab2 in July 2026 and shifted its headquarters to Texas.
What "fab fab" means
Fab2's own description of its business, posted on its homepage, is that it "makes every tool in the fab" and is "building a semiconductor fab fab to make lots of fabs," designing the chambers, pumps, gas lines and lithography equipment itself before assembling them into compact factories it manufactures at scale. Co-founder and Chief Executive Sam Zeloof built chips in his family garage as a high schooler; co-founder Jim Keller designed AMD's Zen architecture, Apple's A4 and A5 chips and Tesla's Autopilot chip before joining Fab2.
A gap between the pitch and the paperwork
Zeloof has described Fab2's Austin site as a 120,000-square-foot dual headquarters and chip plant, a figure the company's own site repeats. But the only Fab2 building permits Travis County records showed as of the Austin American-Statesman's July 31 report covered a $3.9 million renovation of a warehouse at 6301 E. Stassney Lane, split into a 6,000-square-foot first phase finished in August and a 7,555-square-foot second phase due in February 2027, a combined 13,555 square feet. Fab2 did not respond to the newspaper's questions about the discrepancy, and its site does not reconcile the two figures.
| Facility | Listed size | Source |
|---|---|---|
| Austin HQ and fab (company claim) | 120,000 sq ft | Fab2.com |
| Lockhart "fab fab" | 30,000 sq ft | Fab2.com |
| Stassney Lane warehouse permits | 13,555 sq ft | Travis County filings, via Austin American-Statesman |
The next filing to watch
Fab2's Series A puts it in the same week as two other deep-tech rounds The Terminal covered, Ayar Labs' distinction between new money and a secondary sale and Oracle's tripled GPU delivery numbers, both stories where the announced figure and the underlying paperwork told slightly different versions of the same claim. Whether Fab2's actual Austin footprint matches the figure it claims will show up the next time the county issues, or the company files, a permit larger than 13,555 square feet. Fab2 also lists a third site, a 25,000-square-foot facility in San Francisco it calls a garage fab, in addition to the two Texas locations, bringing its own claimed total across three cities to 175,000 square feet.
Sources
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