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Ion Stoica

Co-founder & Chairman (also co-founder & executive chairman of Databricks; Berkeley professor) · Arena (formerly LMArena / Chatbot Arena; Arena Intelligence Inc.)

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Berkeley professor and serial founder (Databricks, Anyscale) who advised the Chatbot Arena students, co-founded the company and chairs it. He gives Arena its enterprise credibility and company-building playbook.

medium confidenceBerkeley, CAAt Arena (formerly LMArena / Chatbot Arena; Arena Intelligence Inc.) since 2025Updated 2026-09-19

Background

Director of UC Berkeley's Sky Computing Lab; turned academic open source (Spark, Ray) into Databricks and Anyscale. He was Wei-Lin Chiang's PhD advisor, connected Angelopoulos to the project, and served as Arena's interim head of machine learning (Felicis).

What they run now

Board-level strategy and founder mentoring at Arena; publicly explains Arena as AI's neutral referee and highlights its move to simulated-preference models and the Max routing product.

Career

  1. 2025 – presentCo-founder & Chairman, Arena
  2. 2013 – presentCo-founder & Executive Chairman, Databricks
  3. presentProfessor; director, Sky Computing Lab, UC Berkeley
  4. presentCo-founder, Anyscale

On the record

Humans in the loop · 2026-07

Humans stay essential for deciding what to solve and verifying results; AI mainly automates the middle step, and experts get the most out of it. source

AI bubble · 2026-07

Expects real value but a correction, as with any new technology that overshoots. source

Arena beyond human votes · 2026-07

Describes Arena building models that simulate user preferences for automated evaluation at scale, powering the Max routing product. source

Interviews & talks

Connections

Why it matters here

Little direct relevance to a creative-data specialist; he matters as the reason Arena is run like an infrastructure company. His stated view that experts gain most from AI and that verification stays human is a quotable counterweight to 'crowd votes are enough'.

How to reach

Not a realistic early contact. If ever, through Berkeley Sky Lab channels. Speculation: not worth spending a warm introduction here before Angelopoulos.

What we could not establish
  • X handle @istoica05 appears in search results under his name but no page tying it to him was verified, so left null.
  • LinkedIn /in/ionstoica/ surfaces with his name and Berkeley but not the company; left null.
  • Education not verified in this pass.

Sources

  1. Felicis founder profile
  2. Benzinga 2026-07-23
  3. TechCrunch 2026-06-29
Also at Arena (formerly LMArena / Chatbot Arena; Arena Intelligence Inc.)
high confidence

Anastasios N. Angelopoulos

Co-founder & CEO

high confidence

Wei-Lin Chiang

Co-founder & CTO