MKSI MKS INC Insider Trading

EVP David Philip Henry sold 6,000 shares of MKSI at $314.43 for $1.9M; stock up 40.5% in 90 days.

David Philip Henry, EVP Global Strategy Marketing & GM at MSD, sold 6,000 shares of MKS INC at $314.43 on 2026-06-01, reducing his holdings from 16,421 to 10,421 shares (a -36.5% reduction). The stock has appreciated 40.5% over the prior 90 days and currently trades at $330.43, near the 52-week high of $339.00. His cross-ticker track record shows only 1 prior buy, and at MKSI specifically, his single measurable prior transaction was a buy on 2023-11-07 with outcome not yet measurable, so no historical timing pattern exists at this ticker. The sale occurred as the stock reached elevated valuations (P/E of 68.27) following a strong 90-day run, though his prior open-market activity has been minimal, limiting inference about conviction or strategic intent behind this particular transaction.

Director Gerald Colella sells 20,000 shares (50% of holdings) for $6.7M via scheduled 10b5-1 plan at MKSI

Gerald Colella, a Director at MKS Inc, executed 7 separate sales totaling 20,000 shares for $6,668,075.10 on 2026-05-27 at prices ranging from $330.38 to $338.58, reducing his holdings from 40,017 to 20,017 shares. This transaction is part of a pre-arranged 10b5-1 trading plan adopted on 2026-02-24, meaning the sales were scheduled and not discretionary. His prior sales at MKSI show mixed timing outcomes: recent sells on 2026-02-24 and 2026-02-20 saw 30-day declines of -11.4% and -10.2% respectively, but 90-day gains of +26.2% and +23.8%, indicating the stock continued upward after those sales. The current price of $324.73 is -4.2% from the 52-week high of $339.00 and represents a 30-day gain of +21.2%, placing this liquidation near recent strength in the stock.

CFO Ramakumar Mayampurath sells 8,810 MKSI shares ($2.8M) via 10b5-1 plan; retains 1 share post-transaction.

Ramakumar Mayampurath, EVP & CFO of MKS Inc, executed a sale of 8,810 shares at $315.48 on 2026-05-22 totaling $2,779,378.80 as part of a pre-arranged 10b5-1 trading plan adopted on 2026-02-20. This sale represents a -100.0% reduction of his pre-transaction holdings of 8,811 shares, leaving him with 1 share post-transaction. The current market price stands at $332.13, which is +1.6% from the 52-week high of $326.84, in a context where the stock has posted a +18.2% 30-day return and +29.8% 90-day return. The scheduled nature of this transaction under a 10b5-1 plan removes discretionary timing from the execution, and the near-complete liquidation of his position warrants investor attention given the substantial holding being disposed of.

John Tseng-Chung Lee, then-CEO, sold 10,000 shares of MKSI at $315.48 under 10b5-1 plan; stock up 18.2% in 30 days post-sale.

John Tseng-Chung Lee, who was CEO at the time of the transaction, sold 10,000 shares (10.0K shares) of MKSI at $315.48 on 2026-05-22 under a pre-arranged 10b5-1 trading plan adopted on 2026-02-20, reducing his holdings by 6.5% to 144,696 shares (144.7K shares). The stock has appreciated 18.2% over the 30 days following the sale and currently trades at $332.13, only 1.6% from its 52-week high of $326.84. His prior trades at MKSI on 2026-02-20 show post-transaction returns of -11.3%, -11.6%, -11.9%, and -12.5% over 30 days, establishing a pattern of short-term stock appreciation after his sales at this ticker. The scheduled nature of this trade under a 10b5-1 plan removes discretionary timing from the interpretation, though the subsequent price action and historical pattern at MKSI remain observable context for investors evaluating insider activity.

EVP, General Counsel sells ~$1.4M in shares as stock trades near 52-week high.

Kathleen Flaherty, the company's EVP, General Counsel & Secretary, sold approximately 4,355 shares worth nearly $1.4 million while the stock trades near its 52-week high after a sharp run-up over recent months. This marks her fifth open-market sale in the past three years, continuing an exclusive pattern of dispositions with no offsetting open-market purchases during the same window. Her prior sale in February was well-timed in the near term as the stock declined in the following month, though it recovered over a longer horizon—a conflicting signal about her timing. MKS is a profitable company with growing revenue and a solid market position, but the valuation appears stretched, which may provide some context for her decision to exit at elevated prices. Without additional disclosure of her motivations or changes in company circumstances, this appears to be a routine rebalancing by a senior executive taking advantage of strong price momentum rather than a signal of fundamental deterioration.