Leopold Aschenbrenner, a 23-year-old AI influencer with no previous professional investing experience, has raised about $1.5 billion for his new hedge fund, Situational Awareness, according to people familiar with the matter. The fund, launched last year, returned roughly 47 percent in the first six months of 2025, making it one of the industry’s best-performing new vehicles and the largest hedge-fund debut so far this year. The rapid capital inflow underscores growing investor appetite for strategies that seek to capitalize on advances in artificial intelligence. Several other start-ups focused on AI-related bets have also drawn substantial commitments, highlighting a broader shift of hedge-fund capital toward the sector.