US share trading set to restart after Chinese app DeepSeek shocks investors

BBC LIVE Summary

Wall Street is set to open after Nvidia - a leading US chip firm for artificial intelligence - suffered the biggest single-day loss in US market history on Monday.

The emergence of a Chinese AI app, DeepSeek, which launched last week, caused tech-focused shares in the US to fall - they also fell in Japan on Tuesday.

The app was reportedly developed for a fraction of the cost of its rivals, raising questions about the future of America's AI dominance and the scale of investments US firms are planning.

DeepSeek has already overtaken rivals including ChatGPT to become the most downloaded free app in the US.

US President Donald Trump said it was a wake-up call for America's technology industry.