Peter Thiel is a co-founder of PayPal and Palantir Technologies who actively invests as an angel through his personal vehicle, Thiel Capital. He is best known for his $500,000 angel investment in Facebook in 2004, which returned over $1 billion. His personal portfolio spans roughly 97 companies, with notable early-stage bets including LinkedIn, Yelp, Twilio, and Zynga. Thiel favours contrarian founders building in areas most investors overlook, particularly defence, AI, and hard science. He operates separately from Founders Fund, the venture firm he also founded.