Investors hoping for initial public offerings from hot artificial-intelligence unicorns Anthropic and OpenAI sometime next year are probably going to be disappointed.

The news that Amazon AMZN is doubling down on its investment in Anthropic is another indication that the startup is likely to stay private for longer, continuing a recent trend in Silicon Valley that has resulted in a weak IPO market. Anthropic develops Claude -- a rival to ChatGPT, the chatbot developed by OpenAI that fueled the AI boom.