Company / CIK 0001049502
MKS INC
- Ticker
- MKSI
- Size, estimated from filings
- Large cap ($10B – $200B)
- Insiders on file
- 16
- Members of Congress who traded it
- 1
- Federal contracts on record
- 1 award
- Lobbying filings on record
- none matched
- SEC filings
- EDGAR ↗
- Latest trade on record
- September 1, 2026
MKS INC (MKSI) has 16 insiders on file who disclosed 177 transactions in the last 12 months (0 open-market buys, 58 sales, about $58.6M at reported prices), and 3 congressional trades in its stock are on record. USAspending shows 1 federal contract award with a combined value of $100K to a recipient with this name that started in the last 180 days; no lobbying filing names it as client this year.
MKS INC in charts
Who is trading this stock
Which people account for the buying and selling over the last 12 months?
BoughtSold
8 people account for the disclosed buying and selling in MKS INC over the last 12 months; the most active is Lee John Tseng-Chung with $23M.
Federal contracts by agency
Which agencies awarded MKS INC contracts that started in the last 180 days?
Federal contract awards to MKS INC that started in the last 180 days have a combined award value of $100K, most from Department of Commerce.
Insiders
| Name | Role | Rows | Bought | Sold | Last filed |
|---|---|---|---|---|---|
| JABRE WISSAM G | Director | 1 | 0 | 0 | October 19, 2026 |
| Mora Elizabeth | Director | 5 | 0 | 4 | September 2, 2026 |
| Donlan Renee Martel | EVP, GC & CCO | 1 | 0 | 0 | August 18, 2026 |
| Lee John Tseng-Chung | President & CEO | 26 | 0 | 8 | August 17, 2026 |
| Williams John Edward | EVP & GM, PSD | 16 | 0 | 4 | August 4, 2026 |
| Schreiner James Alan | EVP & COO | 21 | 0 | 7 | June 16, 2026 |
| McCarthy Michelle M | SVP & Chief Accounting Officer | 11 | 0 | 4 | June 8, 2026 |
| Henry David Philip | EVP, Global Str Mktg & GM, MSD | 18 | 0 | 4 | June 2, 2026 |
| Donahue Joseph B | Director | 2 | 0 | 1 | May 28, 2026 |
| COLELLA GERALD G | Director | 10 | 0 | 9 | May 28, 2026 |
| Mayampurath Ramakumar | EVP & CFO | 11 | 0 | 3 | May 26, 2026 |
| CANNONE PETER III | Director | 3 | 0 | 2 | May 19, 2026 |
| Moloney Jacqueline F | Director | 6 | 0 | 5 | May 15, 2026 |
| Burke Kathleen Flaherty | EVP, GC & Secretary | 28 | 0 | 4 | May 12, 2026 |
| Taranto Eric Robert | EVP & GM, VSD | 18 | 0 | 4 | May 12, 2026 |
| Batra Raj | Director | 1 | 0 | 0 | May 12, 2026 |
Rows are this company's Form 4 rows for each person. "Bought" and "sold" count open-market purchases (code P) and sales only. More in insider buying and insider selling.
Members of Congress who traded MKSI
From periodic transaction reports that name the company's stock. Amounts are the sums of the ranges as filed. Every row is on the MKSI page.
| Member | Seat | Trades | Bought | Sold | Range as filed | Latest |
|---|---|---|---|---|---|---|
| Lisa C. McClain | Representative (MI, District 9), Republican | 3 | 1 | 2 | $3,003–$45K | October 31, 2025 |
Insider transactions
| Filer | Security | Side | Trade date | Disclosed | Lag | Shares | Price | Value | Flags | Source | Share |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Mora Elizabeth | MKSI | Sell S | September 1, 2026 | September 2, 2026 | 1d | 300 | $251 | $75K | 10b5-1 plan | Form 4 ↗ | |
| Donlan Renee Martel | MKSI | Other A | August 17, 2026 | August 18, 2026 | 1d | 954 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Sell S | August 14, 2026 | August 17, 2026 | 3d | 10,000 | $302 | $3.0M | 10b5-1 plan | Form 4 ↗ | |
| Williams John Edward | MKSI | Sell S | August 3, 2026 | August 4, 2026 | 1d | 457 | $288 | $132K | 10b5-1 plan | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Sell S | June 12, 2026 | June 16, 2026 | 4d | 217 | $347 | $75K | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Sell S | June 12, 2026 | June 16, 2026 | 4d | 812 | $346 | $281K | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Sell S | June 12, 2026 | June 16, 2026 | 4d | 2,471 | $346 | $854K | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Sell S | June 10, 2026 | June 11, 2026 | 1d | 781 | $317 | $248K | 10b5-1 plan | Form 4 ↗ | |
| McCarthy Michelle M | MKSI | Sell S | June 5, 2026 | June 8, 2026 | 3d | 2,434 | $315 | $767K | 10b5-1 plan | Form 4 ↗ | |
| Mora Elizabeth | MKSI | Sell S | June 1, 2026 | June 2, 2026 | 1d | 300 | $318 | $95K | 10b5-1 plan | Form 4 ↗ | |
| Henry David Philip | MKSI | Sell S | June 1, 2026 | June 2, 2026 | 1d | 6,000 | $314 | $1.9M | Form 4 ↗ | ||
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 2,800 | $339 | $948K | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 213 | $337 | $72K | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 1,626 | $337 | $547K | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 1,811 | $335 | $608K | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 4,876 | $332 | $1.6M | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 8,210 | $331 | $2.7M | 10b5-1 planindirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 464 | $330 | $153K | 10b5-1 planindirect | Form 4 ↗ | |
| Donahue Joseph B | MKSI | Sell S | May 27, 2026 | May 28, 2026 | 1d | 2,100 | $328 | $689K | Form 4 ↗ | ||
| Henry David Philip | MKSI | Sell S | May 26, 2026 | May 27, 2026 | 1d | 2,500 | $331 | $826K | 10b5-1 plan | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Sell S | May 22, 2026 | May 26, 2026 | 4d | 8,810 | $315 | $2.8M | 10b5-1 plan | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Sell S | May 22, 2026 | May 26, 2026 | 4d | 10,000 | $315 | $3.2M | 10b5-1 plan | Form 4 ↗ | |
| CANNONE PETER III | MKSI | Sell S | May 18, 2026 | May 19, 2026 | 1d | 1,350 | $303 | $410K | Form 4 ↗ | ||
| Moloney Jacqueline F | MKSI | Sell S | May 14, 2026 | May 15, 2026 | 1d | 1,000 | $312 | $312K | Form 4 ↗ | ||
| Moloney Jacqueline F | MKSI | Sell S | May 13, 2026 | May 14, 2026 | 1d | 1,400 | $319 | $447K | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Sell S | May 11, 2026 | May 12, 2026 | 1d | 2,849 | $320 | $911K | Form 4 ↗ | ||
| Moloney Jacqueline F | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| JABRE WISSAM G | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| Mora Elizabeth | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Sell S | May 11, 2026 | May 12, 2026 | 1d | 4,355 | $320 | $1.4M | Form 4 ↗ | ||
| Donahue Joseph B | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| CANNONE PETER III | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| Batra Raj | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| COLELLA GERALD G | MKSI | Other A | May 11, 2026 | May 12, 2026 | 1d | 782 | — | — | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | April 17, 2026 | April 20, 2026 | 3d | 1,741 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Sell F | April 17, 2026 | April 20, 2026 | 3d | 826 | $270 | $223K | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | April 17, 2026 | April 20, 2026 | 3d | 1,741 | — | — | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 1,736 | — | — | derivative | Form 4 ↗ | |
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 1,107 | — | — | derivative | Form 4 ↗ | |
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 968 | — | — | derivative | Form 4 ↗ | |
| McCarthy Michelle M | MKSI | Other A | April 15, 2026 | April 16, 2026 | 1d | 1,673 | — | — | derivative | Form 4 ↗ | |
| McCarthy Michelle M | MKSI | Sell F | April 15, 2026 | April 16, 2026 | 1d | 1,375 | $274 | $377K | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 1,736 | — | — | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 1,107 | — | — | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Option / conversion M | April 15, 2026 | April 16, 2026 | 1d | 968 | — | — | Form 4 ↗ | ||
| Moloney Jacqueline F | MKSI | Sell S | March 12, 2026 | March 13, 2026 | 1d | 340 | $214 | $73K | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Sell S | March 6, 2026 | March 9, 2026 | 3d | 4,568 | $221 | $1.0M | Form 4 ↗ | ||
| Mora Elizabeth | MKSI | Sell S | March 2, 2026 | March 3, 2026 | 1d | 300 | $239 | $72K | 10b5-1 plan | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Sell S | February 24, 2026 | February 25, 2026 | 1d | 4,100 | $255 | $1.0M | Form 4 ↗ | ||
| COLELLA GERALD G | MKSI | Sell S | February 24, 2026 | February 24, 2026 | 0d | 10,000 | $254 | $2.5M | indirect | Form 4 ↗ | |
| COLELLA GERALD G | MKSI | Sell S | February 20, 2026 | February 24, 2026 | 4d | 10,000 | $253 | $2.5M | indirect | Form 4 ↗ | |
| CANNONE PETER III | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 1,250 | $258 | $323K | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 1,453 | $248 | $360K | Form 4 ↗ | ||
| Henry David Philip | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 2,000 | $262 | $523K | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 816 | $250 | $204K | Form 4 ↗ | ||
| McCarthy Michelle M | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 650 | $250 | $162K | Form 4 ↗ | ||
| Moloney Jacqueline F | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 829 | $248 | $205K | Form 4 ↗ | ||
| Williams John Edward | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 2,043 | $256 | $524K | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 4,254 | $250 | $1.1M | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 1,890 | $260 | $491K | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 1,988 | $258 | $513K | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 12,812 | $257 | $3.3M | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Sell S | February 20, 2026 | February 23, 2026 | 3d | 13,310 | $256 | $3.4M | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,303 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,167 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 976 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 348 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 914 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,764 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 1,759 | — | — | derivative | Form 4 ↗ | |
| Taranto Eric Robert | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 2,712 | $261 | $707K | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,303 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,167 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 976 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 348 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 914 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,764 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,054 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,841 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,278 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 456 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,247 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,406 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 2,567 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 4,097 | $261 | $1.1M | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,054 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,841 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,278 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 456 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,247 | — | — | Form 4 ↗ | ||
| Henry David Philip | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,406 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,944 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,741 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,211 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 432 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,330 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,567 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 2,377 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 4,344 | $261 | $1.1M | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,944 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,741 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,211 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 432 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,330 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,567 | — | — | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,106 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 991 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 841 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 300 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 1,474 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 1,195 | $261 | $312K | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,106 | — | — | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 991 | — | — | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 841 | — | — | Form 4 ↗ | ||
| Williams John Edward | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 300 | — | — | Form 4 ↗ | ||
| Mayampurath Ramakumar | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,702 | — | — | derivative | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,958 | — | — | derivative | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 4,279 | — | — | derivative | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 2,516 | $261 | $656K | Form 4 ↗ | ||
| Mayampurath Ramakumar | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,702 | — | — | Form 4 ↗ | ||
| Mayampurath Ramakumar | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,958 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,493 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,336 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,576 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 563 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,788 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 3,451 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 3,328 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 5,318 | $261 | $1.4M | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,493 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 2,336 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,576 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 563 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 1,788 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 3,451 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 12,091 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 16,989 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 7,208 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 3,859 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 7,654 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 22,088 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Other A | February 17, 2026 | February 18, 2026 | 1d | 15,593 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Sell F | February 17, 2026 | February 18, 2026 | 1d | 32,548 | $261 | $8.5M | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 12,091 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 16,989 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 7,208 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 3,859 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 7,654 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | February 17, 2026 | February 18, 2026 | 1d | 22,088 | — | — | Form 4 ↗ | ||
| Taranto Eric Robert | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 3,504 | — | — | derivative | Form 4 ↗ | |
| Henry David Philip | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 5,522 | — | — | derivative | Form 4 ↗ | |
| Schreiner James Alan | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 5,227 | — | — | derivative | Form 4 ↗ | |
| Williams John Edward | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 2,973 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 7,009 | — | — | derivative | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 8,878 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Other A | February 8, 2026 | February 9, 2026 | 1d | 50,972 | — | — | derivative | Form 4 ↗ | |
| Mora Elizabeth | MKSI | Sell S | December 2, 2025 | December 3, 2025 | 1d | 300 | $159 | $48K | 10b5-1 plan | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Option / conversion M | November 17, 2025 | November 18, 2025 | 1d | 8,295 | — | — | derivative | Form 4 ↗ | |
| Mayampurath Ramakumar | MKSI | Sell F | November 17, 2025 | November 18, 2025 | 1d | 2,628 | $143 | $375K | Form 4 ↗ | ||
| Mayampurath Ramakumar | MKSI | Option / conversion M | November 17, 2025 | November 18, 2025 | 1d | 8,295 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 341 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 144 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 82 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 52 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 158 | — | — | derivative | Form 4 ↗ | |
| Burke Kathleen Flaherty | MKSI | Sell F | October 31, 2025 | November 4, 2025 | 4d | 777 | $144 | $112K | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 341 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 144 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 82 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 52 | — | — | Form 4 ↗ | ||
| Burke Kathleen Flaherty | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 158 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 1,651 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 352 | — | — | derivative | Form 4 ↗ | |
| Lee John Tseng-Chung | MKSI | Sell F | October 31, 2025 | November 4, 2025 | 4d | 2,003 | $144 | $288K | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 1,651 | — | — | Form 4 ↗ | ||
| Lee John Tseng-Chung | MKSI | Option / conversion M | October 31, 2025 | November 4, 2025 | 4d | 352 | — | — | Form 4 ↗ | ||
| Schreiner James Alan | MKSI | Sell S | October 22, 2025 | October 23, 2025 | 1d | 711 | $139 | $99K | 10b5-1 plan | Form 4 ↗ | |
| Moloney Jacqueline F | MKSI | Sell S | October 1, 2025 | October 2, 2025 | 1d | 300 | $122 | $37K | 10b5-1 plan | Form 4 ↗ |
Federal contracts (USAspending, awards started in the last 180 days)
| Start date | Awarding agency | Award value | NAICS | Source |
|---|---|---|---|---|
| July 29, 2026 | Department of Commerce | $99,900 | 334513 | USAspending ↗ |
Lobbying (Senate LDA, as client)
No LDA filing posted since October 2025 names "MKS INC" as the client. Filings under a subsidiary or trade-association name are not matched — search lobbying.
Related companies
Companies whose stock was traded by the same people who traded MKSI, by number of filers in common. It shows overlap in public filings and nothing else.
- UNITED THERAPEUTICS Corp UTHR 1 filer in common
- Dell Technologies Inc. DELL 1 filer in common
- Seagate Technology Holdings plc STX 1 filer in common
- Uber Technologies, Inc UBER 1 filer in common
- Datadog, Inc. DDOG 1 filer in common
- Arista Networks, Inc. ANET 1 filer in common
- Meta Platforms, Inc. META 1 filer in common
- Albertsons Companies, Inc. ACI 1 filer in common
Guides for this page
- What is SEC Form 4? Who files: officers, directors and owners of more than 10% of a class of the company's shares.
- Insider buying vs insider selling Selling outweighs buying by a wide margin in normal times.
- Federal contracts: how to read USAspending data Obligation = money the government has committed. Outlay = money actually paid.
- What disclosure data cannot tell you Filings are late by design: up to 45 days for Congress, two business days for insiders.
Sources and method
| Source | Filings | Rows | First filed | Newest filed | Read the originals |
|---|---|---|---|---|---|
| House Clerk, periodic transaction reports | 1 | 3 | November 21, 2025 | November 21, 2025 | House Clerk search |
| SEC EDGAR, Form 4 | 61 | 178 | October 2, 2025 | September 2, 2026 | Form 4 list on EDGAR |
| USAspending, federal contract awards | 1 award | — | — | — | USAspending |
Site built October 22, 2026. Every row in the tables above links to its own filing. To quote a figure, use the Cite button at the top of the page; see how to cite and reuse.
Insiders and their transactions come from SEC EDGAR Form 4 filings for this issuer. Contracts and lobbying are matched by exact normalized name (suffixes like Inc./Corp. ignored) to USAspending recipients and LDA clients — a conservative match that misses subsidiaries on purpose. See methodology and corrections.
Not investment advice. Public records shown as filed; no recommendation is made or implied.