Arthur Breitman
About Arthur Breitman
Arthur Breitman is a computer scientist and entrepreneur and a co-founder of Tezos. He studied applied mathematics at École Polytechnique and the Courant Institute of NYU.
Before Tezos he worked in quantitative finance at Goldman Sachs and Morgan Stanley, and later as a research engineer at Google and Waymo.
He is a member of the Tezos Foundation Council and a director at Trilitech, a London-based team focused on adoption of the Tezos blockchain.
PitchBook lists Breitman as an individual angel investor with four recorded investments: StarkWare (seed, May 2018), Gauntlet (seed, November 2018), Onboardbase (September 2020) and Magic (February 2023). Crunchbase lists three investments, the most recent being Theorem's seed round announced on January 27, 2026. Check sizes and his ownership stakes are not disclosed in the sources reviewed.
In January 2026 Breitman took part in Theorem's $6M seed round as an angel. Theorem is a San Francisco company from Y Combinator's Spring 2025 batch. It builds automated tools that verify the correctness of AI-generated software. Khosla Ventures led the round, with Y Combinator, e14, SAIF and Halcyon also participating.
Tracxn also lists Magic, which it calls Magic AI, among his notable investments. PitchBook dates its Magic investment to February 2023 and classes the company as software development applications.
His recorded deals are mostly seed or early-stage rounds in software, developer tooling, financial software and crypto infrastructure. Tracxn describes his sectors as high tech and enterprise applications, with investments in the United States and Israel. He has made no public statement about check size or a formal investment thesis that we found.
- Theorem: formal verification tools for AI-generated code; seed round announced January 2026.
- Magic: software development company, listed by Tracxn as Magic AI; investment dated February 2023 by PitchBook.
- Gauntlet: financial services company; seed round, November 2018.
- StarkWare: financial software company; seed round, May 2018.
- Onboardbase: business and productivity software; investment dated September 2020.
- venturebeat.com/security/theorem-wants-to-stop-ai-written-bugs-before-
- pitchbook.com/profiles/investor/229091-68
- tracxn.com/d/people/arthur-breitman/__81D14LbbkuCApfQhWkDe_96hapuuwD-h
- crunchbase.com/person/arthur-breitman
- consensus2025.coindesk.com/agenda/speaker/-arthur-breitman
- salt.org/speakers/arthur-breitman
- podcasts.apple.com/ca/podcast/498-arthur-breitman-co-founder-of-tezos-
Investing activity
Arthur Breitman appears in 1 AI deal tracked by the Lounge deals desk. The rounds are mostly Seed, with a median round size of $6M. The most recent is Theorem (Seed, $6M, Jan 2026).
Arthur Breitman most often invests alongside Khosla Ventures, Safe AI Fund, E14 Fund and Blake Borgeson, and the companies they back on Lounge are mostly in AI.
Deals
Frequently asked questions about Arthur Breitman
Who is Arthur Breitman?
He is a co-founder of Tezos and an angel investor. He previously worked at Goldman Sachs, Morgan Stanley, Google and Waymo.
Has Arthur Breitman invested in AI startups?
Yes. He was an angel in Theorem's $6M seed round in January 2026. Tracxn and PitchBook also list Magic, a software development company, among his investments.
What is Arthur Breitman's check size?
It is not public. None of the sources we reviewed give his check sizes.
What stage does Arthur Breitman invest in?
His recorded deals are mainly seed and early-stage rounds, such as StarkWare and Gauntlet in 2018 and Theorem in 2026.
Which sectors does Arthur Breitman back?
His known investments cover AI developer tools, formal verification, financial software and crypto infrastructure. Tracxn lists his sectors as high tech and enterprise applications.
Where can founders contact Arthur Breitman?
He has a public LinkedIn profile and posts on X as @ArthurB. We found no personal website or published pitch process.
Is Arthur Breitman an angel investor?
Yes. Arthur Breitman invests personally as an angel.
What AI companies has Arthur Breitman invested in?
Arthur Breitman's AI investments include Theorem. The 1 round on Lounge are listed on this page with amounts, dates and co-investors.
What stage does Arthur Breitman invest at?
In the rounds tracked on Lounge, Arthur Breitman has invested at Seed, with a median round of $6M.
Who does Arthur Breitman co-invest with?
Arthur Breitman's most frequent co-investors on Lounge are Khosla Ventures (1 deal), Safe AI Fund (1 deal), E14 Fund (1 deal), Blake Borgeson (1 deal) and Y Combinator (1 deal).