Almost A$1 trillion (US$600 billion) was wiped off the value of artificial intelligence microchip maker Nvidia overnight on Monday, when a little-known Chinese start up, DeepSeek, threatened to upend the US tech market.

While Nvidia suffered the biggest one-day loss in sharemarket history, other tech giants – Microsoft, Alphabet and Amazon, who are investing heavily in competing AI tools including ChatGPT and Gemini – were also hit.