MKS Instruments is trading at $234.37, up +9.09%, in pre-market on October 19 as semiconductor stocks rebound. - The rebound follows a steep semiconductor sell-off; SOXX rose 2.4% in overnight trading as investors positioned ahead of major technology earnings. - The October 16 close was $214.83. - No clear company-specific announcement was found; available evidence points to sector sentiment, and MKS Instruments’ latest investor-relations release is dated October 16.