MKS Instruments posts 86% EPS growth, issues margin warning

MKS Instruments delivered the kind of earnings report that should, on paper, make investors smile. Revenue climbed 28% year-over-year to $1.248 billion in the second quarter of 2026. Non-GAAP diluted EPS hit $3.30, up 86% from $1.77 in Q2 2025, and comfortably ahead of the consensus estimate hovering around $2.95 to $2.96. The operating margin expanded by 480 basis points year-over-year to 25.6%. And yet, MKSI shares fell roughly 4.9% in after-hours trading following the announcement, closing around $297 to $298. Wall Street looked past the headline beat and zeroed in on what comes next. What the numbers actually say MKS operates across three business segments, and all three posted double-digit year-over-year growth in Q2. Semiconductor brought in $554 million. Electronics and Packaging contributed $381 million. Specialty Industrial added $313 million. The gross margin came in at 47.6% for the quarter. Free cash flow reached $188 million, and management used some of that to make additional debt prepayments, steadily cleaning up a balance sheet that had been carrying significant leverage from its 2022 acquisition of Atotech. CEO John T.C. Lee pointed to AI investments as the primary...