MKS Instruments is trading at $193.71, down 10.36%, as semiconductor and semiconductor-equipment weakness weighs on shares. - Lam Research’s cautious forecast and concerns about returns on AI spending pressured the broader group. - Broader risk-off sentiment also weighed as technology shares sold off. - MKS Instruments disclosed an agreement to sell Ophir Optics for $650 million on October 19; available reporting does not identify the transaction as the cause of the October 22 decline.