Anthropic’s confidential IPO prospectus shows that 47% of its sales last year came through Amazon and Google, underscoring its reliance on a small group of customers and technology giants. Both companies are major Anthropic investors, key suppliers of computing power and direct competitors in artificial intelligence. The disclosure highlights risks for the Claude maker as it seeks investor backing for an ambitious, capital-intensive plan, Reuters reporters Echo Wang and Krystal Hu reported.