On May 12, 2026, the three major U.S. stock indices closed the day with a mixed bag of gains and losses. The Nasdaq Composite Index experienced a dip, falling by 0.71%, while the S&P 500 Index also saw a slight decline of 0.16%. In contrast, the Dow Jones Industrial Average managed to edge up by 0.11%. The chip and semiconductor equipment sectors, in general, witnessed a downturn, influenced by the waning enthusiasm for AI-driven trading. The Philadelphia Semiconductor Index, a key barometer for the sector, plummeted more than 3%, dragging down shares of industry giants such as Qualcomm and Intel. Similarly, within the optical communication sector, stocks like Lumentum and Credo also underwent corrections. Additionally, Under Armour's stock price took a significant hit, plummeting more than 16%, after the company's adjusted annual profit forecast failed to meet market expectations.