U.S. stocks fell sharply across the board on Monday, Sept. 15, as calls for slower AI expansion, sticky inflation and renewed rate-hike concerns weighed on sentiment. The Philadelphia Semiconductor Index plunged nearly 6%. JPMorgan nevertheless reaffirmed its bullish stance. The bank raised its year-end S&P 500 target in August from 7,800 to 8,000 and expects constituent earnings per share to increase 29% year over year to $350. Mislav Matejka, JPMorgan's head of global and European equity strategy, warned that aggressive short sellers could face a sharp rebound if Trump seeks to cool tensions in the Middle East diplomatically or if third-quarter earnings exceed expectations.