Global tech shares fall as China AI chatbot DeepSeek spooks investors

1. DeepSeek's AI model raises doubts about US tech industry's dominance. 2. Nvidia lost over $400 billion, marking a historic stock decline. 3. DeepSeek claims lower production costs than US rivals, challenging AI investment strategies. 4. Tech stocks, including Google and Microsoft, suffered significant losses in response. 5. DeepSeek's success may prompt reevaluation of US AI investments and valuations.