Carolyn Fong for BIOana Olteanu left an established venture firm to start her own shop — a risk in a tight market.Her track record includes bets on Poolside and MaintainX, which have both achieved unicorn status.Olteanu took the No. 12 spot on Business Insider's 2026 Seed 40 list.Oana Olteanu turned down a job at artificial intelligence lab Poolside. She took the upside instead.Then a partner at early-stage venture firm SignalFire, Olteanu had i…