Jane Street has led a US$105 million Series A for Antithesis, according to a 3 December 2025 PR Newswire release that cast the trading firm as both investor and customer. Chief executive Will Wilson's company markets deterministic simulation testing with roots in FoundationDB-era reliability engineering.
Wilson said: "Software now underpins everything, and as systems become more complex and distributed, the world needs a new testing model that guarantees correctness" Named users in the materials include Jane Street, Ethereum and MongoDB — high-reliability environments where flaky integration tests are not enough.
Jane Street commentary in the release said: "Jane Street runs some of the most demanding distributed systems in the world, and Antithesis has helped us uncover issues that no other testing method could find" The raise is framed as expanding infrastructure so reliability is expected rather than hoped for.
For banks and market-infrastructure builders adopting AI agents and distributed systems, Antithesis is selling a testing model closer to continuous correctness proofs than conventional QA dashboards.
Figures and customer claims in this piece are those stated by the company or acquirer in the cited materials.