Anthropic has soared to a $1.5 trillion valuation on secondary markets. Almost no one wants to sell.

Dario Amodei is the co-founder and CEO of Anthropic, Bloomberg/Getty Images Since Anthropic is still private, the vast majority of investors buy on secondary markets. Anthropic's secondary valuation has soared to $1.5 trillion over the past month, a 25% increase. Anthropic's valuation has…