Jane Street's $18B Fluidstack bet: the broker books the contracts, the miners carry the debt

From rented gamers' GPUs to a 2.4x mark in 60 days

Sixty days after a $750 million round priced it at $7.5 billion, Fluidstack has closed $1.5 billion led by Jane Street at an $18 billion post-money valuation↗ ¹. Founded at Oxford in 2017 renting gamers' spare GPUs, it became Anthropic's builder in November 2025, with $50 billion of US data centres to deliver and the first publicly known Google TPU halls outside Google itself ².

What the $18 billion is priced against

The mark is 27 times the $660 million an investor memo projects for 2026↗, against $200 million expected in 2025 and $66.2 million audited in 2024 ¹³. Cumulative equity raised: about $2.6 billion ¹.

The broker owns no chips, and the new lead wears the scar

Fluidstack owns no silicon. It leases power and shells from converted bitcoin miners, nearly 1GW locked from TeraWulf, Cipher Mining and Hut 8 ¹³. July's round was led by Situational Awareness ², the fund whose margin-call unwind helped cost its own investor Jane Street $15 billion, the trading firm's first negative month since 2016 ⁴. Jane Street wrote the bigger cheque anyway.

The miners hold $22.7 billion of the paper

TeraWulf's Lake Mariner carries two ten-year Fluidstack leases: about 360MW, $6.7 billion of contracted revenue, Google backstopping $3.2 billion ³. Cipher's Barber Lake, about 207MW, was extended on 25 September 2026 from ten years to twenty, lifting contracted revenue past $9 billion↗, with Cipher absorbing the first $359.3 million of overruns ⁵. Hut 8's River Bend holds a fifteen-year, $7.0 billion Fluidstack lease for 245MW, Google-backstopped and financed with $7.5 billion of project bonds↗ plus a $1.07 billion JPMorgan-led revolver ⁶.

Twenty-year locks and a BBB- stamp, against one customer

The bull case is real: revenue up tenfold in two years, a twenty-year lock at Barber Lake ⁵, and Google backstops on all three miner leases ³⁶. Hut 8's contracted capacity runs on triple-net, take-or-pay terms, and its River Bend notes took the first BBB- rating for a single-sponsor data centre project bond ⁶. TeraWulf cashed out too, selling its 50.1 percent stake in the Abernathy joint venture back to a Fluidstack-led group ⁷.

Against that, roughly $50 billion of Fluidstack's long-term contracted revenue rests on one customer, Anthropic ³. Opponents blocked or delayed 75 US projects worth about $130 billion in the first quarter of 2026 alone ³. And Anthropic signs direct when it wants: a $19 billion, twenty-year lease for up to 401MW at TeraWulf's Kentucky campus↗, no broker in between ⁷⁸.

Who carries the mark if it deflates

Jane Street has booked more than $40 billion of trading revenue this year, above 2025's record $39.6 billion ⁴, and this month pre-let 465,000 square feet of A&O Shearman's London office ⁹. Its AI book now runs from an Anthropic stake to a $6 billion CoreWeave cloud deal to the middleman itself, a layout closer to a cross-asset book than a venture portfolio ³.

The Fed and the Bank of England are asking banks how exposed they are to it↗, and the SEC has subpoenaed lenders over Situational Awareness's leverage ¹⁰. First rent at Barber Lake falls due this quarter ⁵. Fluidstack owns the contracts, the miners own the concrete, Jane Street owns the mark.