The rout extended well beyond traditional tech names. Siemens Energy, which supplies electrical hardware for AI infrastructure, plunged 22 per cent. Schneider Electric, a French maker of electrical power products that has invested heavily in services for data centres, fell 9.2 per cent.

The Chinese startup DeepSeek released an AI reasoning model that appears to rival the abilities of a frontier model from OpenAI, the maker of ChatGPT.

Chinese AI assistant DeepSeek has become the top rated free app on Apple's App Store in the US and elsewhere, beating out ChatGPT and other rivals. It's powered by the open-source DeepSeek V3 model, which reportedly requires far less computing power than competitors and was developed for under $6 million,