Why Is Teradyne ( $TER ) Stock Down -11.44% Today? (Find out why any stock moved today on Tickeron.) TER shares plunged roughly 11.4% in Monday trading, one of the steepest single-session declines for the stock in recent memory. The selloff was driven by a broad retreat across AI and semiconductor names amid renewed valuation concerns and questions over the durability of hyperscaler capital spending. $KRCX $STM $OMTO $TXN $FORM $RMBS $NXPI