SEC Form 4
MKS Inc. (MKSI) insider trading
In the 12 months to Oct 23, 2026, 13 MKSI insiders reported open-market sales of $43.5M across 33 filings; no open-market purchases were filed.
Latest filing · Last 12 months · Source: SEC EDGAR · How we count
- Open-market sales
- $43.5M
- 33 filings · 13 insiders
- Open-market purchases
- $0
- 0 filings
- Pre-arranged sales (10b5-1)
- 13 of 33
- $18.0M of $43.5M sold (41%)
Who traded MKSI, and when
- Sale
- Sale, pre-arranged (10b5-1)
MKSI daily close from Oct 23, 2025 to Oct 23, 2026, between $137.20 and $444.80, last $198.24. 33 sale and 0 purchase filings by 13 insiders, marked at their filing dates. John Tseng-Chung Lee, President & CEO: sold $13.9M across 3 filings, first filed Feb 23, 2026, last Aug 17, 2026. Gerald G. Colella, Director: sold $11.7M across 2 filings, first filed Feb 24, 2026, last May 28, 2026. David Philip Henry, EVP, Global Str Mktg & GM, MSD: sold $3.2M across 3 filings, first filed Feb 23, 2026, last Jun 2, 2026. Ramakumar Mayampurath, EVP & CFO: sold $2.8M across 1 filing, first filed May 26, 2026, last May 26, 2026. James Alan Schreiner, EVP & COO: sold $2.6M across 4 filings, first filed Oct 23, 2025, last Jun 16, 2026. Kathleen Flaherty Burke, EVP, GC & Secretary: sold $2.5M across 2 filings, first filed Feb 23, 2026, last May 12, 2026. 7 others: sold $6.8M across 18 filings, first filed Dec 3, 2025, last Sep 2, 2026.
Largest mark · tap a row for others
John Tseng-Chung Lee · President & CEO
Sale $7,703,242
30,000 shares at $256.77 avg
Filed Feb 23, 2026 · traded Feb 20
Close on filing date $253.71
John Tseng-Chung Lee · President & CEO
President & CEO
$13.9M soldGerald G. Colella · Director
Director
$11.7M soldDavid Philip Henry · EVP, Global Str Mktg & GM, MSD
EVP, Global Str Mktg & GM, MSD
$3.2M soldRamakumar Mayampurath · EVP & CFO
EVP & CFO
$2.8M soldJames Alan Schreiner · EVP & COO
EVP & COO
$2.6M soldKathleen Flaherty Burke · EVP, GC & Secretary
EVP, GC & Secretary
$2.5M sold7 others
Combined, one mark per week
$6.8M soldHas MKS Inc.'s CEO sold stock?
Yes. John Tseng-Chung Lee (CEO) sold 50,000 shares ($13.9M) between Feb 2026 and Aug 2026, $6.2M of it under a pre-arranged 10b5-1 plan.
Open-market trades
33 filings in the last 12 months| Insider | Role | Sold | Bought | Filings | Pre-arranged (10b5-1) | Last filed |
|---|---|---|---|---|---|---|
| John Tseng-Chung Lee | President & CEO | $13.9M | — | 3 | 44% of sales | |
| Gerald G. Colella | Director | $11.7M | — | 2 | 57% of sales | |
| David Philip Henry | EVP, Global Str Mktg & GM, MSD | $3.2M | — | 3 | 26% of sales | |
| Ramakumar Mayampurath | EVP & CFO | $2.8M | — | 1 | 100% of sales | |
| James Alan Schreiner | EVP & COO | $2.6M | — | 4 | 13% of sales | |
| Kathleen Flaherty Burke | EVP, GC & Secretary | $2.5M | — | 2 | — | |
| Eric Robert Taranto | EVP & GM, VSD | $2.3M | — | 3 | — | |
| Michelle M. McCarthy | VP & Chief Accounting Officer → SVP & Chief Accounting Officer | $1.1M | — | 2 | 68% of sales | |
| Jacqueline F. Moloney | Director | $1.0M | — | 4 | — | |
| Peter Cannone III | Director | $732.2K | — | 2 | — | |
| Joseph B. Donahue | Director | $688.7K | — | 1 | — | |
| John Edward Williams | EVP & GM, PSD | $655.5K | — | 2 | 20% of sales | |
| Elizabeth Mora | Director | $290.2K | — | 4 | 100% of sales |
| Filed | Insider | Type | Shares | Avg price | Value | Held after | Source |
|---|---|---|---|---|---|---|---|
traded | Elizabeth Mora Director | SalePre-arranged (10b5-1) | 300 | $250.96 | $75.3K | 18,845 | |
traded | John Tseng-Chung Lee President & CEO | SalePre-arranged (10b5-1) | 10,000 | $302.01 | $3.0M | 134,776 | |
traded | John Edward Williams EVP & GM, PSD | SalePre-arranged (10b5-1) | 457 | $288.31 | $131.8K | 4,098 | |
traded | James Alan Schreiner EVP & COO | Sale | 3,500 | $345.82 | $1.2M | 20,230 | |
traded | James Alan Schreiner EVP & COO | SalePre-arranged (10b5-1) | 781 | $317.42 | $247.9K | 22,701 | |
traded | Michelle M. McCarthy SVP & Chief Accounting Officer | SalePre-arranged (10b5-1) | 2,434 | $315.23 | $767.3K | 2 | |
traded | Elizabeth Mora Director | SalePre-arranged (10b5-1) | 300 | $318.02 | $95.4K | 19,145 | |
traded | David Philip Henry EVP, Global Str Mktg & GM, MSD | Sale | 6,000 | $314.43 | $1.9M | 10,422 | |
traded | Gerald G. Colella Director | SalePre-arranged (10b5-1) | 20,000 | $333.40 | $6.7M | 24,656 | |
traded | Joseph B. Donahue Director | Sale | 2,100 | $327.95 | $688.7K | 10,033 | |
traded | David Philip Henry EVP, Global Str Mktg & GM, MSD | SalePre-arranged (10b5-1) | 2,500 | $330.50 | $826.3K | 16,341 | |
traded | John Tseng-Chung Lee President & CEO | SalePre-arranged (10b5-1) | 10,000 | $315.48 | $3.2M | 144,696 | |
traded | Ramakumar Mayampurath EVP & CFO | SalePre-arranged (10b5-1) | 8,810 | $315.48 | $2.8M | 1 | |
traded | Peter Cannone III Director | Sale | 1,350 | $303.40 | $409.6K | 7,794 | |
traded | Jacqueline F. Moloney Director | Sale | 1,000 | $312.20 | $312.2K | 8,775 | |
traded | Jacqueline F. Moloney Director | Sale | 1,400 | $318.99 | $446.6K | 9,775 | |
traded | Kathleen Flaherty Burke EVP, GC & Secretary | Sale | 4,355 | $319.94 | $1.4M | 49,439 | |
traded | Eric Robert Taranto EVP & GM, VSD | Sale | 2,849 | $319.93 | $911.3K | 12,596 | |
traded | Jacqueline F. Moloney Director | Sale | 340 | $213.77 | $72.7K | 10,393 | |
traded | Eric Robert Taranto EVP & GM, VSD | Sale | 4,568 | $220.52 | $1.0M | 15,445 | |
traded | Elizabeth Mora Director | SalePre-arranged (10b5-1) | 300 | $239.44 | $71.8K | 18,663 | |
traded | James Alan Schreiner EVP & COO | Sale | 4,100 | $255.00 | $1.0M | 23,402 | |
traded | Gerald G. Colella Director | Sale | 20,000 | $253.43 | $5.1M | 40,017 | |
traded | John Tseng-Chung Lee President & CEO | Sale | 30,000 | $256.77 | $7.7M | 158,574 | |
traded | Kathleen Flaherty Burke EVP, GC & Secretary | Sale | 4,254 | $250.00 | $1.1M | 53,794 | |
traded | John Edward Williams EVP & GM, PSD | Sale | 2,043 | $256.41 | $523.7K | 3,640 | |
traded | Jacqueline F. Moloney Director | Sale | 829 | $247.55 | $205.2K | 10,733 | |
traded | Michelle M. McCarthy VP & Chief Accounting Officer | Sale | 1,466 | $250.00 | $366.5K | 816 | |
traded | David Philip Henry EVP, Global Str Mktg & GM, MSD | Sale | 2,000 | $261.56 | $523.1K | 18,841 | |
traded | Eric Robert Taranto EVP & GM, VSD | Sale | 1,453 | $247.55 | $359.6K | 20,013 | |
traded | Peter Cannone III Director | Sale | 1,250 | $258.06 | $322.6K | 8,362 | |
traded | Elizabeth Mora Director | SalePre-arranged (10b5-1) | 300 | $158.81 | $47.6K | 18,963 | |
traded | James Alan Schreiner EVP & COO | SalePre-arranged (10b5-1) | 711 | $138.68 | $98.6K | 22,535 |
GET /stocks/filings/vX/form-4?tickers=MKSI&filing_date.gte=2025-10-23&sort=filing_date.desc&limit=500{
"status": "OK",
"results": [
{
"tickers": [
"MKSI"
],
"issuer_cik": "0001049502",
"owner_cik": "0001548935",
"accession_number": "0001049502-26-000119",
"form_type": "4",
"filing_date": "2026-09-02",
"period_of_report": "2026-09-01",
"issuer_name": "MKS INC",
"issuer_trading_symbol": "MKSI",
"owner_name": "Mora Elizabeth",
"is_director": true,
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": true,
"transaction_date": "2026-09-01",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 300,
"transaction_price_per_share": 250.96,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 18845.353,
"transaction_value": 75288,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 23, 2026."
}
]
},
{
"tickers": [
"MKSI"
],
"issuer_cik": "0001049502",
"owner_cik": "0001414656",
"accession_number": "0001049502-26-000113",
"form_type": "4",
"filing_date": "2026-08-17",
"period_of_report": "2026-08-14",
"issuer_name": "MKS INC",
"issuer_trading_symbol": "MKSI",
"owner_name": "Lee John Tseng-Chung",
"is_director": true,
"is_officer": true,
"officer_title": "President & CEO",
"security_type": "non_derivative",
"record_type": "transaction",
"security_title": "Common Stock",
"transaction_timeliness": "O",
"aff_10b5_one": true,
"transaction_date": "2026-08-14",
"transaction_code": "S",
"equity_swap_involved": false,
"transaction_shares": 10000,
"transaction_price_per_share": 302.01,
"transaction_acquired_disposed": "D",
"shares_owned_following_transaction": 134776.2667,
"transaction_value": 3020100,
"direct_or_indirect": "D",
"footnotes": [
{
"id": "F1",
"description": "This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 20, 2026."
}
]
}
]
}
// trimmed to 2 resultsThe response includes every Form 4 record; this page keeps open-market purchases and sales on common stock and removes duplicate joint-filer rows.
Other insider activity (not market trades) · 67 records
- Option exercises48 records
- Tax withholding12 records
- Grants and awards7 records
Reported on Form 4 but not purchases or sales in the market, so not counted in the totals above.
Build this yourself
This page joins two Massive endpoints: Form 4 filings and daily prices. Ask an agent to watch for new filings:
Using the Massive API (massive.com/docs/llms.txt), check Form 4 filings for MKSI every day with transaction_code=P and tell me when an insider files an open-market purchase, with their role, shares, price and the filing link.
How to read this page
- Open-market purchase or sale
- A buy or sell of the company's stock at market price. Grants, option exercises, shares withheld for tax, gifts and employee stock plan purchases are listed separately and not counted.
- Pre-arranged (10b5-1)
- The insider marked the filing as made under a trading plan set up in advance (SEC Rule 10b5-1). The mark covers the whole filing, and an unmarked filing may still be under a plan.
- Role
- The title on each filing. Someone whose title changed shows more than one.
- Filing date
- Insiders have two business days to report a trade. Totals and the chart use the filing date, when the trade became public.