Quick Takeaways
- MKSI - MKS INC has 21 insiders with reported activity on this page.
- Net insider value flow over the last year: -$19,660,508.
- Recent transaction rows are available for direct filing-level review.
- Info
- Insider Trading
- Financials
- Holders
Insider Transactions Reported by 21 Insiders of MKS INC
- Symbol
- MKSI on Nasdaq
- Location
- Andover, MA
What Changed
- Buy value: ; sell value: $19,660,507.
- Net share flow: -83,608.
Why This Matters
- This page gives a plain-language issuer insider context before you inspect transaction-level evidence.
- Use the filing links below to verify timestamps, codes, and ownership impacts directly from SEC forms.
Source Evidence
Filed on Form 4
See Original Filing
Issuer insider activity is sourced from SEC Forms 3, 4, and 5.
Insider trading overview
Last 12 monthsNet insider flow leans to selling over the last 12 months. Net value: -$19,660,508.
Buys
$0
Shares: 0
Insiders: 0
Sells
$19,660,508
Shares: 83,608
Insiders: 11
Net
-$19,660,508
Shares: -83,608
Insiders: -11
| Window (months) | Buy shares | Sell shares | Buy $ | Sell $ | Net $ |
|---|---|---|---|---|---|
| 0-3 | 0 | 72,602 | $0 | $18,333,555 | -$18,333,555 |
| 3-6 | 0 | 300 | $0 | $47,643 | -$47,643 |
| 6-9 | 0 | 7,449 | $0 | $946,740 | -$946,740 |
| 9-12 | 0 | 3,257 | $0 | $332,569 | -$332,569 |
MKS INC executives and other stock owners filed with the SEC include:
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Carlyle Group Inc. | 10%+ Owner | $713,103,113 | Mixed | 08 May 2023 | ||
| Carlyle Partners VI Cayman Holdings, L.P. | 10%+ Owner | $713,103,113 | Mixed | 08 May 2023 | ||
| John Tseng-Chung Lee | President & CEO, Director | $49,598,861 | -$7,703,242 | -13% | Mixed | 20 Feb 2026 |
| Kathleen Flaherty Burke | EVP, GC & Secretary | $15,291,432 | -$1,063,500 | -6.5% | Mixed | 20 Feb 2026 |
| Gerald G. Colella | Director | $12,166,961 | -$5,068,674 | -29% | Mixed | 20 Feb 2026 |
| Geoffrey Wild | Director | $11,838,269 | Mixed | 17 Aug 2022 | ||
| James Alan Schreiner | Evp & Coo | $7,453,018 | -$1,346,049 | -15% | Mixed | 24 Feb 2026 |
| David Philip Henry | EVP, Global Str Mktg & GM, MSD | $6,305,526 | -$1,383,120 | -18% | Mixed | 20 Feb 2026 |
| Ramakumar Mayampurath | Evp & Cfo | $4,857,795 | Mixed | 17 Feb 2026 | ||
| Elizabeth Mora | Director | $4,468,763 | -$173,964 | -3.7% | Filing P/S | 02 Mar 2026 |
| Eric Robert Taranto | Evp & Gm, Vsd | $4,363,642 | -$1,366,941 | -24% | Mixed | 06 Mar 2026 |
| Mark Milton Gitin | Evp & Gm, Psd | $3,328,164 | Mixed | 15 Feb 2024 | ||
| Seth H. Bagshaw | EVP, CFO & Treasurer | $3,135,791 | Mixed | 22 Feb 2024 | ||
| Jacqueline F. Moloney | Director | $2,221,771 | -$342,196 | -13% | Filing P/S | 12 Mar 2026 |
| Peter Cannone III | Director | $2,157,915 | -$322,575 | -13% | Filing P/S | 20 Feb 2026 |
| John Edward Williams | Evp & Gm, Psd | $1,614,519 | -$523,744 | -24% | Mixed | 17 Apr 2026 |
| Michelle M. Warner | Director | $1,443,294 | Mixed | 07 May 2024 | ||
| Michelle M. McCarthy | SVP & Chief Accounting Officer | $1,440,515 | -$366,503 | -20% | Mixed | 15 Apr 2026 |
| Raj Batra | Director | $1,130,598 | Mixed | 12 May 2025 | ||
| Joseph B. Donahue | Director | $830,874 | Mixed | 12 May 2025 | ||
| Wissam G. Jabre | Director | $328,519 | Mixed | 12 May 2025 |
Top shareholders of MKS INC (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Ownership % is shown only when it is directly reported or safely comparable across share classes.
Methodology: rows are grouped by holder and ranked by the holder's primary source value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
| Holder | Source | Role / Reporting | Ownership % | Shares | Holdings Value | 12M Net Δ | As of | Details |
|---|---|---|---|---|---|---|---|---|
| VANGUARD GROUP INC |
13F
|
Company |
11%
|
7,487,305
|
$1,196,471,339 | — | 31 Dec 2025 | |
| BlackRock, Inc. |
13F
13D/G
|
Company |
8.8%
from 13D/G
|
6,138,839
|
$980,986,438 | — | 31 Dec 2025 | |
| Invesco Ltd. |
13D/G
13F
|
Company |
6.5%
|
4,394,205
|
$806,336,618 | $0 | 31 Dec 2025 | |
| Carlyle Group Inc. |
3/4/5
|
10%+ Owner |
—
class O/S missing
|
6,482,732
|
$713,103,113 | — | 08 May 2023 | |
| Carlyle Partners VI Cayman Holdings, L.P. |
3/4/5
|
10%+ Owner |
—
class O/S missing
|
6,482,732
|
$713,103,113 | — | 08 May 2023 | |
| Capital International Investors |
13F
13D/G
|
Company |
4.7%
from 13D/G
|
3,239,230
|
$517,628,954 | — | 31 Dec 2025 | |
| FMR LLC |
13F
|
Company |
4.8%
|
3,198,335
|
$511,094,010 | — | 31 Dec 2025 | |
| PRICE T ROWE ASSOCIATES INC /MD/ |
13D/G
13F
|
T. Rowe Price Associates, Inc. · Company |
4.1%
|
2,753,871
|
$505,335,328 | -$252,359,660 | 31 Dec 2025 | |
| VICTORY CAPITAL MANAGEMENT INC |
13F
13D/G
|
Company |
5.6%
from 13D/G
|
2,562,399
|
$409,471,360 | — | 31 Dec 2025 | |
| WELLINGTON MANAGEMENT GROUP LLP |
13F
|
Company |
3.8%
|
2,552,021
|
$407,812,955 | — | 31 Dec 2025 | |
| STATE STREET CORP |
13F
|
Company |
3%
|
2,017,590
|
$322,410,882 | — | 31 Dec 2025 | |
| JPMORGAN CHASE & CO |
13F
|
Company |
2.3%
|
1,551,443
|
$247,920,742 | — | 31 Dec 2025 | |
| Neuberger Berman Group LLC |
13F
|
Company |
2.2%
|
1,461,189
|
$233,497,989 | — | 31 Dec 2025 | |
| GEODE CAPITAL MANAGEMENT, LLC |
13F
|
Company |
1.9%
|
1,254,049
|
$200,437,891 | — | 31 Dec 2025 | |
| DIMENSIONAL FUND ADVISORS LP |
13F
|
Company |
1.7%
|
1,117,487
|
$178,581,199 | — | 31 Dec 2025 | |
| FRANKLIN RESOURCES INC |
13F
|
Company |
1.6%
|
1,041,725
|
$166,467,655 | — | 31 Dec 2025 | |
| COOKE & BIELER LP |
13F
|
Company |
1.4%
|
966,703
|
$154,479,139 | — | 31 Dec 2025 | |
| NORGES BANK |
13F
|
Company |
1.4%
|
922,737
|
$147,453,373 | — | 31 Dec 2025 | |
| Madison Asset Management, LLC |
13F
|
Company |
1.4%
|
921,450
|
$147,247,760 | — | 31 Dec 2025 | |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC |
13F
|
Company |
1.3%
|
870,654
|
$139,130,509 | — | 31 Dec 2025 | |
| WESTFIELD CAPITAL MANAGEMENT CO LP |
13F
|
Company |
1.3%
|
839,773
|
$134,195,725 | — | 31 Dec 2025 | |
| MILLENNIUM MANAGEMENT LLC |
13F
|
Company |
1.2%
|
817,251
|
$130,596,710 | — | 31 Dec 2025 | |
| Bank of New York Mellon Corp |
13F
|
Company |
1.2%
|
788,648
|
$126,026,114 | — | 31 Dec 2025 | |
| PRINCIPAL FINANCIAL GROUP INC |
13F
|
Company |
1.1%
|
765,595
|
$122,352,810 | — | 31 Dec 2025 | |
| Point72 Asset Management, L.P. |
13F
|
Company |
0.93%
|
625,799
|
$100,002,680 | — | 31 Dec 2025 | |
| ROYCE & ASSOCIATES LP |
13F
|
Company |
0.92%
|
616,605
|
$98,533,479 | — | 31 Dec 2025 | |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE |
13F
|
Company |
0.9%
|
606,214
|
$96,881,320 | — | 31 Dec 2025 | |
| NORDEA INVESTMENT MANAGEMENT AB |
13F
|
Company |
0.89%
|
599,842
|
$96,604,554 | — | 31 Dec 2025 | |
| Southpoint Capital Advisors LP |
13F
|
Company |
0.89%
|
600,000
|
$95,880,000 | — | 31 Dec 2025 | |
| MORGAN STANLEY |
13F
|
Company |
0.88%
|
590,521
|
$94,365,520 | — | 31 Dec 2025 | |
| NORTHERN TRUST CORP |
13F
|
Company |
0.84%
|
565,986
|
$90,444,563 | — | 31 Dec 2025 | |
| FRONTIER CAPITAL MANAGEMENT CO LLC |
13F
|
Company |
0.82%
|
550,735
|
$88,007,378 | — | 31 Dec 2025 | |
| Channing Capital Management, LLC |
13F
|
Company |
0.79%
|
531,179
|
$84,882,404 | — | 31 Dec 2025 | |
| NATIXIS ADVISORS, LLC |
13F
|
Company |
0.78%
|
522,415
|
$83,482,000 | — | 31 Dec 2025 | |
| BALYASNY ASSET MANAGEMENT L.P. |
13F
|
Company |
0.76%
|
511,620
|
$81,756,876 | — | 31 Dec 2025 | |
| BANK OF AMERICA CORP /DE/ |
13F
|
Company |
0.71%
|
480,227
|
$76,740,340 | — | 31 Dec 2025 | |
| CITADEL ADVISORS LLC |
13F
|
Company |
0.68%
|
457,873
|
$73,168,105 | — | 31 Dec 2025 | |
| Blue Grotto Capital, LLC |
13F
|
Company |
0.62%
|
415,500
|
$66,396,901 | — | 31 Dec 2025 | |
| AMERICAN CENTURY COMPANIES INC |
13F
|
Company |
0.59%
|
397,564
|
$63,531,047 | — | 31 Dec 2025 | |
| WELLS FARGO & COMPANY/MN |
13F
|
Company |
0.58%
|
391,182
|
$62,510,858 | — | 31 Dec 2025 | |
| JANE STREET GROUP, LLC |
13F
|
Company |
0.57%
|
383,115
|
$61,221,776 | — | 31 Dec 2025 | |
| SUMMIT PARTNERS PUBLIC ASSET MANAGEMENT, LLC |
13F
|
Company |
0.57%
|
381,500
|
$60,963,700 | — | 31 Dec 2025 | |
| NOMURA HOLDINGS INC |
13F
|
Company |
0.54%
|
364,033
|
$58,172,473 | — | 31 Dec 2025 | |
| Nuveen, LLC |
13F
|
Company |
0.51%
|
341,424
|
$54,559,555 | — | 31 Dec 2025 | |
| BARCLAYS PLC |
13F
|
Company |
0.51%
|
340,318
|
$54,382,816 | — | 31 Dec 2025 | |
| Delta Global Management LP |
13F
|
Company |
0.49%
|
327,390
|
$52,316,922 | — | 31 Dec 2025 | |
| UBS Group AG |
13F
|
Company |
0.48%
|
323,713
|
$51,729,337 | — | 31 Dec 2025 | |
| John Tseng-Chung Lee |
3/4/5
|
President & CEO, Director |
—
mixed-class rows
|
239,524
mixed-class rows
|
$49,598,861 | -$7,703,242 | 20 Feb 2026 | |
| ROYAL BANK OF CANADA |
13F
|
Company |
0.46%
|
309,842
|
$49,514,000 | — | 31 Dec 2025 | |
| VALUE HOLDINGS MANAGEMENT CO. LLC |
13F
|
Company |
0.44%
|
297,714
|
$47,575,000 | — | 31 Dec 2025 |
Recent Insider Transactions by Companies or Individuals for MKS INC
Showing up to 300 most recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | Value $ | * Price $ | Shares | Shares Owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| John Edward Williams | MKSI | Common Stock | Tax liability | -15.4% | -826 | 4,555 | 17 Apr 2026 | Direct | ||
| John Edward Williams | MKSI | Common Stock | Options Exercise | 47.8% | 1,741 | 5,381 | 17 Apr 2026 | Direct | ||
| John Edward Williams | MKSI | Restricted Stock Unit | Options Exercise | -20.4% | -1,741 | 6,812 | 17 Apr 2026 | Direct | ||
| Michelle M. McCarthy | MKSI | Common Stock | Tax liability | -36.1% | -1,375 | 2,436 | 15 Apr 2026 | Direct | ||
| Michelle M. McCarthy | MKSI | Common Stock | Options Exercise | 3,811 | 3,811 | 15 Apr 2026 | Direct | |||
| Michelle M. McCarthy | MKSI | Restricted Stock Unit | Options Exercise | -34% | -3,811 | 7,388 | 15 Apr 2026 | Direct | ||
| Michelle M. McCarthy | MKSI | Restricted Stock Unit | Award | 17.6% | 1,673 | 11,199 | 15 Apr 2026 | Direct | ||
| Jacqueline F. Moloney | MKSI | Common Stock | Sale | -3.17% | $72,705 | $213.77 | -340 | 10,393 | 12 Mar 2026 | Direct |
| Eric Robert Taranto | MKSI | Common Stock | Sale | -22.8% | $1,007,318 | $220.52 | -4,568 | 15,445 | 06 Mar 2026 | Direct |
| Elizabeth Mora | MKSI | Common Stock | Sale | -1.58% | $71,832 | $239.44 | -300 | 18,663 | 02 Mar 2026 | Direct |
| James Alan Schreiner | MKSI | Common Stock | Sale | -14.9% | $1,045,500 | $255.00 | -4,100 | 23,402 | 24 Feb 2026 | Direct |
| Gerald G. Colella | MKSI | Common Stock | Sale | -20% | $2,539,675 | $253.97 | -10,000 | 40,017 | 24 Feb 2026 | By The Gerald G. Colella 2019 Trust |
| Gerald G. Colella | MKSI | Common Stock | Sale | -16.7% | $2,528,999 | $252.90 | -10,000 | 50,017 | 20 Feb 2026 | By The Gerald G. Colella 2019 Trust |
| Peter Cannone III | MKSI | Common Stock | Sale | -13% | $322,574 | $258.06 | -1,250 | 8,362 | 20 Feb 2026 | Direct |
| Eric Robert Taranto | MKSI | Common Stock | Sale | -6.77% | $359,623 | $247.55 | -1,453 | 20,013 | 20 Feb 2026 | Direct |
| David Philip Henry | MKSI | Common Stock | Sale | -9.6% | $523,120 | $261.56 | -2,000 | 18,841 | 20 Feb 2026 | Direct |
| Michelle M. McCarthy | MKSI | Common Stock | Sale | -100% | $366,503 | $250.00 | -1,466 | 0 | 20 Feb 2026 | Direct |
| Jacqueline F. Moloney | MKSI | Common Stock | Sale | -7.17% | $205,219 | $247.55 | -829 | 10,733 | 20 Feb 2026 | Direct |
| John Edward Williams | MKSI | Common Stock | Sale | -35.9% | $523,744 | $256.41 | -2,043 | 3,640 | 20 Feb 2026 | Direct |
| Kathleen Flaherty Burke | MKSI | Common Stock | Sale | -7.33% | $1,063,500 | $250.00 | -4,254 | 53,794 | 20 Feb 2026 | Direct |
| John Tseng-Chung Lee | MKSI | Common Stock | Sale | -16.2% | $7,703,242 | $256.77 | -30,000 | 154,696 | 20 Feb 2026 | Direct |
| Eric Robert Taranto | MKSI | Common Stock | Tax liability | -11.2% | -2,712 | 21,465 | 17 Feb 2026 | Direct | ||
| Eric Robert Taranto | MKSI | Common Stock | Options Exercise | 36.6% | 6,473 | 24,177 | 17 Feb 2026 | Direct | ||
| Eric Robert Taranto | MKSI | Restricted Stock Unit | Options Exercise | -44.6% | -6,473 | 8,029 | 17 Feb 2026 | Direct | ||
| Eric Robert Taranto | MKSI | Restricted Stock Unit | Award | 13.8% | 1,759 | 14,502 | 17 Feb 2026 | Direct | ||
| David Philip Henry | MKSI | Common Stock | Tax liability | -16.4% | -4,097 | 20,841 | 17 Feb 2026 | Direct | ||
| David Philip Henry | MKSI | Common Stock | Options Exercise | 59.3% | 9,282 | 24,939 | 17 Feb 2026 | Direct | ||
| David Philip Henry | MKSI | Restricted Stock Unit | Options Exercise | -43.4% | -9,282 | 12,093 | 17 Feb 2026 | Direct | ||
| David Philip Henry | MKSI | Restricted Stock Unit | Award | 13.6% | 2,567 | 21,375 | 17 Feb 2026 | Direct | ||
| James Alan Schreiner | MKSI | Common Stock | Tax liability | -13.6% | -4,344 | 27,502 | 17 Feb 2026 | Direct | ||
| James Alan Schreiner | MKSI | Common Stock | Options Exercise | 40.8% | 9,225 | 31,846 | 17 Feb 2026 | Direct | ||
| James Alan Schreiner | MKSI | Restricted Stock Unit | Options Exercise | -44.7% | -9,225 | 11,396 | 17 Feb 2026 | Direct | ||
| James Alan Schreiner | MKSI | Restricted Stock Unit | Award | 13% | 2,377 | 20,622 | 17 Feb 2026 | Direct | ||
| John Edward Williams | MKSI | Common Stock | Tax liability | -17.4% | -1,195 | 5,683 | 17 Feb 2026 | Direct | ||
| John Edward Williams | MKSI | Common Stock | Options Exercise | 89% | 3,238 | 6,878 | 17 Feb 2026 | Direct | ||
| John Edward Williams | MKSI | Restricted Stock Unit | Options Exercise | -27.5% | -3,238 | 8,553 | 17 Feb 2026 | Direct | ||
| John Edward Williams | MKSI | Restricted Stock Unit | Award | 14.3% | 1,474 | 11,791 | 17 Feb 2026 | Direct | ||
| Ramakumar Mayampurath | MKSI | Common Stock | Tax liability | -22.2% | -2,516 | 8,811 | 17 Feb 2026 | Direct | ||
| Ramakumar Mayampurath | MKSI | Common Stock | Options Exercise | 99.9% | 5,660 | 11,327 | 17 Feb 2026 | Direct | ||
| Ramakumar Mayampurath | MKSI | Restricted Stock Unit | Options Exercise | -19.2% | -5,660 | 23,898 | 17 Feb 2026 | Direct | ||
| Ramakumar Mayampurath | MKSI | Restricted Stock Unit | Award | 16.9% | 4,279 | 29,559 | 17 Feb 2026 | Direct | ||
| Kathleen Flaherty Burke | MKSI | Common Stock | Tax liability | -8.39% | -5,318 | 58,048 | 17 Feb 2026 | Direct | ||
| Kathleen Flaherty Burke | MKSI | Common Stock | Options Exercise | 23.9% | 12,206 | 63,366 | 17 Feb 2026 | Direct | ||
| Kathleen Flaherty Burke | MKSI | Restricted Stock Unit | Options Exercise | -44.6% | -12,206 | 15,129 | 17 Feb 2026 | Direct | ||
| Kathleen Flaherty Burke | MKSI | Restricted Stock Unit | Award | 13.9% | 3,328 | 27,335 | 17 Feb 2026 | Direct | ||
| John Tseng-Chung Lee | MKSI | Common Stock | Tax liability | -15% | -32,548 | 184,696 | 17 Feb 2026 | Direct | ||
| John Tseng-Chung Lee | MKSI | Common Stock | Options Exercise | 47.4% | 69,889 | 217,244 | 17 Feb 2026 | Direct | ||
| John Tseng-Chung Lee | MKSI | Restricted Stock Unit | Options Exercise | -45.2% | -69,889 | 84,828 | 17 Feb 2026 | Direct | ||
| John Tseng-Chung Lee | MKSI | Restricted Stock Unit | Award | 11.2% | 15,593 | 154,717 | 17 Feb 2026 | Direct | ||
| Eric Robert Taranto | MKSI | Restricted Stock Unit | Award | 37.9% | 3,504 | 12,743 | 08 Feb 2026 | Direct |
* An asterisk sign (*) next to the price indicates that the price is likely invalid.