Sources: AI training data startup Micro1 raised $100M+ at a $4B valuation, up from $500M in September 2025 (Anna Tong/Forbes)

AI training data startup Micro1 has reportedly raised over $100 million at a $4 billion valuation. This marks a significant increase from its $500 million valuation in September 2025. The company, founded by Ali Ansari, has seen its annual recurring revenue (ARR) surge from $7 million to over $500 million. Notably, two co-founders of xAI participated in this latest funding round, highlighting strong investor confidence in Micro1's growth and potential in the AI sector.