Synopsys is trading 4.05% down at $432.90 as semiconductor shares sell off on October 22, 2026. - The sector is down 4.20%, with investors reacting to Lam Research’s cautious outlook tied to supply-chain constraints and renewed concerns about AI spending returns. - Broader technology weakness and risk-off trading are adding pressure; no clear Synopsys-specific announcement explains the drop. - Morgan Stanley’s October 21 price-target increase was positive, not a matching catalyst for today’s decline.