Days after Chinese upstart DeepSeek revealed a breakthrough in cheap AI computing that shook the U.S. technology industry, the chief executives of Microsoft and Meta defended massive spending that they said was key to staying competitive in the new field.

OpenAI says it has found evidence that Chinese artificial intelligence start-up DeepSeek used the US company’s proprietary models to train its own open-source competitor. The San Francisco-based ChatGPT maker told the FT it had seen some evidence of “distillation”,