Sam AltmanSam Altman

CEO of OpenAI. Former President of Y Combinator (2014-2019). Personal angel portfolio via Hydrazine Capital (co-founded with brother Jack, 2012) and Apollo Projects. 400+ companies valued at ~$2.8B. Key hardware investments: Humane ($100M+ across 3 rounds), Rain AI (neuromorphic chips, OpenAI signed $51M LOI), Helion Energy ($375M personal — nuclear fusion), Oklo (nuclear fission, Chairman). For hardware founders: Altman's investment signals massive AI-hardware conviction — he personally backed Humane, Rain AI chips, and poured his entire liquid net worth into energy/biotech.