Sam Altman

For years Sam Altman has been one of the most prominent seed investors. He’s perhaps best known for his five years as the president of the famous startup accelerator Y Combinator, a role he left in 2019. Altman’s keen eye for investments helped him jump 80 spots up to No. 13 on this year’s Seed 100 list. One example: After first backing the fusion-energy startup Helion Energy in 2015, he invested $375 million in the startup's $500 million Series E round in November, which boosted its valuation to $3 billion. When not investing, he leads OpenAI, an organization that works with open-source artificial intelligence.