U.S. stocks sold off broadly on Monday as calls from AI leaders to slow development, persistent inflation and renewed rate-hike concerns weighed on markets. The Philadelphia Semiconductor Index fell nearly 6%. JPMorgan nevertheless reaffirmed its bullish stance, with Mislav Matejka, the bank's global and European head of equity strategy, warning that aggressive short selling could leave investors exposed to a sharp rebound. Matejka said surging oil prices are weighing on valuations, but argued that shorting U.S. equities remains highly risky while the expansion in corporate earnings has not been disproved. He pointed to two potential catalysts for a reversal: U.S. President Donald Trump's diplomatic efforts to cool tensions in the Middle East and third-quarter earnings that exceed expectations. JPMorgan raised its year-end S&P 500 target to 8,000 from 7,800 in August and expects constituent companies' earnings per share to jump 29% year over year to $350.