Why Is Coherent Corp. ( $COHR ) Stock Down -11.38% Today? (Find out why any stock moved today on Tickeron.) COHR shares fell 11.38% to $270.61, down $34.76 from the prior session's close of $305.37. The primary catalyst was a rare, coordinated call from leading AI executives to slow the development of frontier AI models, stoking fears of reduced AI-infrastructure capital spending. $MKSI $KEYS $ST $VPG $ESE