Overseas stocks and US stock futures fell sharply Friday after technological advances announced by a Chinese artificial intelligence company intensified concerns that the AI spending spree driving this year’s market rally could be at risk. The announcement came from Chinese company Moonshot, which unveiled Kimi K3, its most capable AI model, and one it said closed much of the gap with models such as OpenAI’s ChatGPT and Anthropic’s Claude. Market indexes in South Korea and Taiwan closed down more than 6%, while markets in Japan closed down 4% on the news. Nasdaq futures were down 1.6% early Friday, with futures...