MKS Instruments, Inc. (MKSI) Ownership
MKSI ownership summary
as of October 18, 2026- Institutions
- 107.5% of shares outstanding
- Insiders
- 0.48% of shares outstanding
- Shares outstanding
- 67.6M
- Float
- 67.2M shares available to trade
- Short interest
- 8.55% 5.1M shares short
- Days to cover
- 4.00 short interest down 16.3% vs prior month
- Institutions 107.54%
- Insiders 0.48%
MKSI top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 10.25% | 6.9M | $1.49B | +288,300 (+4.3%) | June 30, 2026 |
| 2 | Amvescap Plc. | 6.89% | 4.7M | $1.00B | +940,205 (+25.3%) | June 30, 2026 |
| 3 | Vanguard Portfolio Management, LLC | 5.48% | 3.7M | $796.4M | +21,834 (+0.6%) | June 30, 2026 |
| 4 | JPMorgan Chase & Co | 4.99% | 3.4M | $724.8M | +1.3M (+60.9%) | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 4.51% | 3.0M | $655.1M | +35,359 (+1.2%) | June 30, 2026 |
| 6 | State Street Corp | 3.16% | 2.1M | $458.6M | +76,931 (+3.7%) | June 30, 2026 |
| 7 | Point72 Asset Management, L.P. | 2.95% | 2.0M | $429.0M | +386,512 (+24.0%) | June 30, 2026 |
| 8 | Capital Research & Mgmt Co - Division 3 | 2.83% | 1.9M | $411.4M | −53,583 (−2.7%) | June 30, 2026 |
| 9 | T. Rowe Price Associates, Inc. | 2.79% | 1.9M | $406.0M | +189,753 (+11.2%) | June 30, 2026 |
| 10 | Aspex Management (HK) Ltd | 2.69% | 1.8M | $391.1M | +281,652 (+18.3%) | June 30, 2026 |
| 11 | Geode Capital Management, LLC | 2.28% | 1.5M | $330.6M | −247 (−0.0%) | June 30, 2026 |
| 12 | FMR Inc | 2.22% | 1.5M | $322.1M | −434,345 (−22.5%) | June 30, 2026 |
| 13 | Wellington Management Company LLP | 2.09% | 1.4M | $304.2M | −417,103 (−22.8%) | June 30, 2026 |
| 14 | Capital World Investors | 2.02% | 1.4M | $293.5M | +89,090 (+7.0%) | June 30, 2026 |
| 15 | Whale Rock Capital Management LLC | 1.88% | 1.3M | $273.1M | −35,351 (−2.7%) | June 30, 2026 |
| 16 | Neuberger Berman Group LLC | 1.72% | 1.2M | $250.3M | −268,461 (−18.7%) | June 30, 2026 |
| 17 | Alkeon Capital Management, LLC | 1.59% | 1.1M | $230.3M | +1.1M (0.0%) | June 30, 2026 |
| 18 | NORGES BANK | 1.41% | 955K | $205.1M | +31,930 (+3.5%) | June 30, 2026 |
| 19 | Westfield Capital Management Company, L.P. | 1.37% | 929K | $199.5M | −118,146 (−11.3%) | June 30, 2026 |
| 20 | Sachem Head Capital Management LP | 1.20% | 813K | $174.6M | +812,700 (0.0%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 13 holders added 5.5M shares and 7 cut 1.3M.
MKSI top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | American Funds SMALLCAP World A | 3.61% | 2.4M | $523.7M | −16,058 (−0.7%) | September 30, 2026 |
| 2 | iShares Core S&P Mid-Cap ETF | 3.56% | 2.4M | $517.4M | −864 (−0.0%) | September 30, 2026 |
| 3 | Vanguard MStar Total Stk Mkt Idx Invest | 3.17% | 2.1M | $460.8M | −5,480 (−0.3%) | August 31, 2026 |
| 4 | Vanguard Small Cap Index | 2.25% | 1.5M | $327.0M | −32,317 (−2.1%) | September 30, 2026 |
| 5 | Vanguard MStar Small Cap Growth Indx Inv | 1.25% | 847K | $181.9M | +400,865 (+89.9%) | September 30, 2026 |
| 6 | Invesco S&P MidCap Momentum ETF | 1.16% | 783K | $168.3M | — | September 30, 2026 |
| 7 | Vanguard Information Technology ETF | 1.03% | 694K | $149.0M | +1,597 (+0.2%) | September 30, 2026 |
| 8 | American Funds Growth Fd of Amer A | 0.90% | 608K | $130.6M | — | September 30, 2026 |
| 9 | Invesco Small Cap Value A | 0.83% | 558K | $119.9M | −588,272 (−51.3%) | August 31, 2026 |
| 10 | ACAP Strategic A | 0.77% | 523K | $112.4M | +523,018 (0.0%) | June 30, 2026 |
| 11 | State Street® SPDR® S&P MIDCAP 400® ETF | 0.74% | 500K | $107.4M | +6,005 (+1.2%) | September 30, 2026 |
| 12 | Invesco Value Opportunities A | 0.71% | 478K | $102.6M | −404,837 (−45.9%) | August 31, 2026 |
| 13 | JPMorgan Growth Advantage A | 0.64% | 436K | $93.6M | +98,021 (+29.0%) | August 31, 2026 |
| 14 | Fidelity VIP Mid Cap Initial | 0.53% | 360K | $77.3M | — | August 31, 2026 |
| 15 | State Street SPDR Port S&P 400 Md CpETF | 0.53% | 357K | $76.8M | −504 (−0.1%) | September 30, 2026 |
| 16 | JPMorgan Mid Cap Value L | 0.51% | 347K | $74.6M | −24,390 (−6.6%) | August 31, 2026 |
| 17 | Victory Sycamore Established Value R | 0.50% | 335K | $72.0M | −145,000 (−30.2%) | June 30, 2026 |
| 18 | Fidelity Extended Market Index | 0.48% | 328K | $70.4M | −4,006 (−1.2%) | August 31, 2026 |
| 19 | T. Rowe Price Mid-Cap Value | 0.47% | 315K | $67.6M | — | September 30, 2026 |
| 20 | Neuberger Genesis Inv | 0.43% | 289K | $62.0M | −26,876 (−8.5%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
MKSI insider transactions
latest 20| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-03-12 | Jacqueline F Moloney | Sell | $213.77 | 340 | $72,682 |
| 2026-03-06 | Eric Robert Taranto | Sell | $220.52 | 4,568 | $1.0M |
| 2026-03-02 | Elizabeth Mora | Sell | $239.44 | 300 | $71,832 |
| 2026-02-24 | Gerald G Colella | Sell | $253.97 | 10,000 | $2.5M |
| 2026-02-20 | Michelle M Mccarthy | Sell | $250.00 | 1,466 | $366,500 |
| 2026-02-20 | Peter Cannone III | Sell | $258.06 | 1,250 | $322,575 |
| 2026-02-20 | Kathleen Flaherty Burke | Sell | $250.00 | 4,254 | $1.1M |
| 2026-02-20 | John Tseng-Chung Lee | Sell | $256.77 | 30,000 | $7.7M |
| 2026-02-20 | John Edward Williams | Sell | $256.41 | 2,043 | $523,846 |
| 2026-02-20 | Jacqueline F Moloney | Sell | $247.55 | 829 | $205,219 |
| 2026-02-20 | Gerald G Colella | Sell | $252.90 | 10,000 | $2.5M |
| 2026-02-20 | Eric Robert Taranto | Sell | $247.55 | 1,453 | $359,690 |
| 2026-02-20 | David Philip Henry | Sell | $261.56 | 2,000 | $523,120 |
| 2025-12-02 | Elizabeth Mora | Sell | $158.81 | 300 | $47,643 |
| 2025-10-31 | Lisa C. McClain | Sell | $143.71 | — | — |
| 2025-10-30 | Lisa C. McClain | Sell | $139.31 | — | — |
| 2025-10-30 | Lisa C. McClain | Buy | $139.31 | — | — |
| 2025-10-01 | Jacqueline F Moloney | Sell | $122.14 | 300 | $36,642 |
| 2025-09-18 | David Philip Henry | Sell | $130.00 | 5,000 | $650,000 |
| 2025-09-02 | Elizabeth Mora | Sell | $99.85 | 300 | $29,955 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
MKSI shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns MKSI
Institutional investors own 107.5% of MKS Instruments's shares and insiders 0.48%. The largest holder is BlackRock Inc with 10.25% of the shares (6.9M), as of June 30, 2026. Among the top 20 institutions, 13 added shares and 7 reduced their stake in the latest filings. Short interest is 8.55% of the float, or 4.00 days of average trading volume. The share count rose 27.3% since 2014.
Related: MKSI analyst forecast, MKSI key metrics, MKSI dividend history. See the MKSI stock overview for the latest quote and news.
MKSI ownership FAQ
Who owns the most MKS Instruments stock?
The largest shareholders of MKS Instruments are BlackRock Inc (10.25%), Amvescap Plc. (6.89%), Vanguard Portfolio Management, LLC (5.48%), JPMorgan Chase & Co (4.99%), Vanguard Capital Management, LLC (4.51%).
What percentage of MKS Instruments is owned by institutions?
Institutions hold 107.5% of MKS Instruments's shares outstanding; insiders hold 0.48%.
Which funds own MKS Instruments?
The largest fund holders of MKS Instruments are American Funds SMALLCAP World A (3.61%), iShares Core S&P Mid-Cap ETF (3.56%), Vanguard MStar Total Stk Mkt Idx Invest (3.17%), Vanguard Small Cap Index (2.25%), Vanguard MStar Small Cap Growth Indx Inv (1.25%).
What is MKS Instruments's short interest?
5.1M shares of MKS Instruments were sold short, 8.55% of the float; at the average daily volume it would take 4.00 days to cover.
Are insiders buying or selling MKS Instruments?
Of the latest 20 reported insider transactions in MKS Instruments (since September 2, 2025), 1 were purchases and 19 were sales.
How many shares of MKS Instruments are outstanding?
MKS Instruments has 67.6M shares outstanding, of which 67.2M are in the public float.