US stocks open lower: Philadelphia Semiconductor Index falls 1.75%, memory and optical stocks slide

The breadth of the semiconductor pullback — memory and optical names falling together rather than a single segment — suggests the move is being read as sector-wide rather than company-specific, which matters for anyone holding the AI-infrastructure trade through chip suppliers. The GM drop after results and Braze's deal-driven spike point to a market separating earnings disappointments from M&A premiums on the same morning. Whether the memory and optical weakness extends beyond early trading, or proves a one-session repricing, is the open question.