MKS INC (MKSI)
$255.76-$15.23 (-5.62%) Today
John Edward Williams - Officer
James Alan Schreiner - OfficerJames Alan Schreiner - OfficerJames Alan Schreiner - OfficerJames Alan Schreiner - Officer
David Philip Henry - OfficerMKS Inc delivers foundational technology solutions for leading edge semiconductor manufacturing, electronics and packaging, and specialty industrial applications. The company provides instruments, components, subsystems, systems, process control solutions, and specialty chemicals technology that improve process performance and optimize productivity. Its solutions address challenges of miniaturization and complexity in device manufacturing, enabling increased power, speed, and feature enhancement. MKS Inc operates through three divisions: Vacuum Solutions Division (VSD), Photonics Solutions Division (PSD), and Materials Solutions Division (MSD). The company operates in the United States, which generates maximum revenue, as well as China and other countries.
| Form 4 transaction type | Transactions | Shares | Total value |
|---|---|---|---|
| Open-market sale | 9 | 23,472 | $7.36M |
| Grant or award | 1 | 954.04 |
Dollar totals are shown for open-market purchases and sales only. Grants, option exercises, gifts and tax withholding are reported by share count because they are not trades at a market price.
84 Form 4 filings on record, the earliest from Oct 2, 2024, newest first. Filing history page 2 of 3.
| Date | Insider | Transaction | Security | Shares | Price | Value |
|---|---|---|---|---|---|---|
 Gerald G. Colella - Director | Open-market sale | Common Stock | 10,000 | $252.90 | $2.53M | |
| Gerald G. Colella - Director | Open-market sale | Common Stock | 10,000 | $253.97 | $2.54M | |
 Peter Cannone III - Director | Open-market sale | Common Stock | 1,250 | $258.06 | $323K | |
| Eric Robert Taranto - Officer | Open-market sale | Common Stock | 1,453 | $247.55 | $360K | |
| David Philip Henry - Officer | Open-market sale | Common Stock | 2,000 | $261.56 | $523K | |
| Michelle M. McCarthy - Officer | Open-market sale | Common Stock | 650 | $249.57 | $162K | |
| Michelle M. McCarthy - Officer | Open-market sale | Common Stock | 816 | $250.35 | $204K | |
 Jacqueline F. Moloney - Director | Open-market sale | Common Stock | 829 | $247.55 | $205K | |
| John Edward Williams - Officer | Open-market sale | Common Stock | 2,043 | $256.41 | $524K | |
| Kathleen Flaherty Burke - Officer | Open-market sale | Common Stock | 4,254 | $250.00 | $1.06M | |
| John Tseng-Chung Lee - Officer | Open-market sale | Common Stock | 13,310 | $256.05 | $3.41M | |
| John Tseng-Chung Lee - Officer | Open-market sale | Common Stock | 12,812 | $256.93 | $3.29M | |
| John Tseng-Chung Lee - Officer | Open-market sale | Common Stock | 1,988 | $257.81 | $513K | |
| John Tseng-Chung Lee - Officer | Open-market sale | Common Stock | 1,890 | $259.70 | $491K | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 1,764 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 914.05 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 348.33 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 976 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 1,167 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Common Stock | 1,303 | - | - | |
| Eric Robert Taranto - Officer | Tax withholding / forfeiture | Common Stock | 2,712 | $260.74 | $707K | |
| Eric Robert Taranto - Officer | Grant or award | Restricted Stock Unit | 1,759 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 1,764 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 914.05 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 348.33 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 976 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 1,167 | - | - | |
| Eric Robert Taranto - Officer | Option exercise | Restricted Stock Unit | 1,303 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 2,406 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 1,247 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 1,278 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 456.45 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 1,841 | - | - | |
| David Philip Henry - Officer | Option exercise | Common Stock | 2,054 | - | - | |
| David Philip Henry - Officer | Tax withholding / forfeiture | Common Stock | 4,097 | $260.74 | $1.07M | |
| David Philip Henry - Officer | Grant or award | Restricted Stock Unit | 2,567 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 2,406 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 1,247 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 456.45 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 1,278 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 1,841 | - | - | |
| David Philip Henry - Officer | Option exercise | Restricted Stock Unit | 2,054 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 1,211 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 1,741 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 1,944 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 2,567 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 1,330 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 432.48 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 1,211 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 1,741 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Common Stock | 1,944 | - | - | |
| James Alan Schreiner - Officer | Tax withholding / forfeiture | Common Stock | 4,344 | $260.74 | $1.13M | |
| James Alan Schreiner - Officer | Grant or award | Restricted Stock Unit | 2,377 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 2,567 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 1,330 | - | - | |
| James Alan Schreiner - Officer | Option exercise | Restricted Stock Unit | 432.48 | - | - | |
| John Edward Williams - Officer | Option exercise | Common Stock | 300.39 | - | - | |
| John Edward Williams - Officer | Option exercise | Common Stock | 841 | - | - | |
| John Edward Williams - Officer | Option exercise | Common Stock | 990.72 | - | - | |
| John Edward Williams - Officer | Option exercise | Common Stock | 1,106 | - | - | |
| John Edward Williams - Officer | Tax withholding / forfeiture | Common Stock | 1,195 | $260.74 | $312K | |
| John Edward Williams - Officer | Grant or award | Restricted Stock Unit | 1,474 | - | - | |
| John Edward Williams - Officer | Option exercise | Restricted Stock Unit | 300.39 | - | - | |
| John Edward Williams - Officer | Option exercise | Restricted Stock Unit | 841 | - | - | |
| John Edward Williams - Officer | Option exercise | Restricted Stock Unit | 990.72 | - | - | |
| John Edward Williams - Officer | Option exercise | Restricted Stock Unit | 1,106 | - | - | |
| Ramakumar Mayampurath - Officer | Option exercise | Common Stock | 2,958 | - | - | |
| Ramakumar Mayampurath - Officer | Option exercise | Common Stock | 2,702 | - | - | |
| Ramakumar Mayampurath - Officer | Tax withholding / forfeiture | Common Stock | 2,516 | $260.74 | $656K | |
| Ramakumar Mayampurath - Officer | Grant or award | Restricted Stock Unit | 4,279 | - | - | |
| Ramakumar Mayampurath - Officer | Option exercise | Restricted Stock Unit | 2,958 | - | - | |
| Ramakumar Mayampurath - Officer | Option exercise | Restricted Stock Unit | 2,702 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 3,451 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 1,788 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 2,336 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 562.54 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 1,576 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 2,336 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 2,493 | - | - | |
| Kathleen Flaherty Burke - Officer | Tax withholding / forfeiture | Common Stock | 5,318 | $260.74 | $1.39M | |
| Kathleen Flaherty Burke - Officer | Grant or award | Restricted Stock Unit | 3,328 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 3,451 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 1,788 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 562.54 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 1,576 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 2,493 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 7,654 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 3,859 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 7,208 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 22,088 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 7,654 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 3,859 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 7,208 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 16,989 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 12,091 | - | - | |
| John Tseng-Chung Lee - Officer | Tax withholding / forfeiture | Common Stock | 32,548 | $260.74 | $8.49M | |
| John Tseng-Chung Lee - Officer | Grant or award | Restricted Stock Unit | 15,593 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 22,088 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 16,989 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 12,091 | - | - | |
| Eric Robert Taranto - Officer | Grant or award | Restricted Stock Unit | 3,504 | - | - | |
| David Philip Henry - Officer | Grant or award | Restricted Stock Unit | 5,522 | - | - | |
| James Alan Schreiner - Officer | Grant or award | Restricted Stock Unit | 5,227 | - | - | |
| John Edward Williams - Officer | Grant or award | Restricted Stock Unit | 2,973 | - | - | |
| Kathleen Flaherty Burke - Officer | Grant or award | Restricted Stock Unit | 7,009 | - | - | |
| Ramakumar Mayampurath - Officer | Grant or award | Restricted Stock Unit | 8,878 | - | - | |
| John Tseng-Chung Lee - Officer | Grant or award | Restricted Stock Unit | 50,972 | - | - | |
 Elizabeth Mora - Director | Open-market sale | Common Stock | 300 | $158.81 | $48K | |
| Ramakumar Mayampurath - Officer | Option exercise | Common Stock | 8,295 | - | - | |
| Ramakumar Mayampurath - Officer | Tax withholding / forfeiture | Common Stock | 2,628 | $142.74 | $375K | |
| Ramakumar Mayampurath - Officer | Option exercise | Restricted Stock Unit | 8,295 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 341 | - | - | |
| Kathleen Flaherty Burke - Officer | Tax withholding / forfeiture | Common Stock | 777 | $143.71 | $112K | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 158 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 52 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 82 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 144 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Restricted Stock Unit | 341 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 158 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 52 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 82 | - | - | |
| Kathleen Flaherty Burke - Officer | Option exercise | Common Stock | 144 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 352 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Restricted Stock Unit | 1,651 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 352 | - | - | |
| John Tseng-Chung Lee - Officer | Option exercise | Common Stock | 1,651 | - | - | |
| John Tseng-Chung Lee - Officer | Tax withholding / forfeiture | Common Stock | 2,003 | $143.71 | $288K | |
| James Alan Schreiner - Officer | Open-market sale | Common Stock | 711 | $138.68 | $99K | |
| Jacqueline F. Moloney - Director | Open-market sale | Common Stock | 300 | $122.14 | $37K | |
| David Philip Henry - Officer | Open-market sale | Common Stock | 5,000 | $130.00 | $650K |
A Form 144 is notice of an INTENDED sale, not a completed one. It often precedes the Form 4 that reports the trade actually happening.
| Filed | Filer | Relationship | Shares | Market value | Notice |
|---|---|---|---|---|---|
| Lee John Tseng-Chung | Officer, Director | 10,000 | $3.02M | View on EDGAR | |
| Williams John Edward | Officer | 457 | $132K | View on EDGAR | |
| - | - | - | - | View on EDGAR |
MKS INC (MKSI) had 8 insider filings in the last 90 days, with the most recent on 2026-08-18. The full record for MKSI runs to 84 Form 4 filings, the earliest from 2024-10-02. InsiderAlpha tracks every Form 4, Form 144, and 8-K filing in real time.
No insider purchases of MKSI were filed in the last 90 days.
9 insider sales of MKSI were filed in the last 90 days, totaling $7.36M.
This page tracks MKSI Form 4 insider transactions, Form 144 sale notices, and 8-K material event disclosures in one timeline. Annual 10-K and quarterly 10-Q reports live on the company's SEC EDGAR page.
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Every Form 4 below links to the original document on SEC EDGAR, so the numbers on this page can be checked against the filing they came from.
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