ISTANBUL US stocks ended mixed Monday as the Dow fell while optimism over AI and a rise in shares of chip companies drove the Nasdaq and S&P 500 higher. Tech stocks soared following Microsoft’s announcement last week that it plans to invest around $80 billion to create AI-enabled data centers. Taiwan's Foxconn, the world's largest contract electronics maker, posted record revenue in the fourth quarter, which also contributed to the rise in technology stocks. Microsoft shares gained 1.1%, while