Since last September, the tech giant has pumped $8 billion into the artificial intelligence start-up, a sign of intense competition in developing tools that are reshaping the tech sector.

Amazon is investing an additional $4 billion in Anthropic, doubling its investment in the artificial-intelligence startup as it aims to compete in the AI arms race. Amazon is a minority owner of San Francisco-based Anthropic,

Amazon.com Inc. is investing an additional $4 billion in artificial intelligence startup Anthropic, boosting its stake in one of OpenAI’s chief rivals.