MKS Inc (MKSI) director’s trust sells 20,000 shares under 10b5-1 plan

Filing Impact

(Very High)

Filing Sentiment

(Very Negative)

Form Type

Rhea-AI Filing Summary

MKS Inc director Gerald G. Colella reported a net sale of 20,000 shares of MKS Inc common stock through an affiliated trust. On May 27, 2026, The Gerald G. Colella 2019 Trust executed seven open‑market sales at prices around $330 per share, leaving the trust holding 39,553 shares afterward.

Separately, Colella is shown with 8,998.886 shares held directly as a position entry rather than a new trade. A footnote states that at least one of the sales was made under a pre‑arranged Rule 10b5‑1 trading plan adopted on February 24, 2026, indicating the transactions were scheduled in advance.

Insider Trade Summary 10b5-1

Net Seller: 20,000 shares ($6,668,075)

Net Sell 8 txns

Insider COLELLA GERALD G

Role null

Sold 20,000 shs ($6.67M)

Type	Security	Shares	Price	Value
Sale	Common Stock	464	$330.3828	$153K
Sale	Common Stock	8,210	$331.4488	$2.72M
Sale	Common Stock	4,876	$332.0414	$1.62M
Sale	Common Stock	1,811	$335.458	$608K
Sale	Common Stock	1,626	$336.5429	$547K
Sale	Common Stock	213	$337.0505	$72K
Sale	Common Stock	2,800	$338.58	$948K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 39,553 shares (Indirect, By The Gerald G. Colella 2019 Trust); Common Stock — 8,998.886 shares (Direct, null)

Footnotes (1)

This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 24, 2026. This transaction was executed in multiple trades at prices ranging from $329.90 to $330.90. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $330.95 to $331.90. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $331.98 to $332.44. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $334.60 to $335.55. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected. his transaction was executed in multiple trades at prices ranging from $335.82 to $336.82. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $337.00 to $337.73. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

Key Figures

Shares sold by trust: 20,000 shares Number of sale transactions: 7 sales Representative sale price: $338.58 per share +3 more

6 metrics

Shares sold by trust 20,000 shares Total MKS Inc common shares sold by The Gerald G. Colella 2019 Trust on May 27, 2026

Number of sale transactions 7 sales Open-market or private sale line items by the 2019 Trust on May 27, 2026

Representative sale price $338.58 per share Price for one reported open-market sale of MKS Inc common stock

Trust holdings after sales 39,553 shares MKS Inc common shares held by The Gerald G. Colella 2019 Trust after transactions

Direct holdings 8,998.886 shares MKS Inc common shares held directly by Gerald G. Colella as a position entry

Rule 10b5-1 plan adoption date February 24, 2026 Date the reporting person adopted the trading plan referenced in the footnote

Key Terms

Rule 10b5-1 trading plan, weighted average sale price, open-market sale, indirect ownership

4 terms

Rule 10b5-1 trading plan regulatory

"This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 24, 2026."

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

weighted average sale price financial

"The price reported above reflects the weighted average sale price."

open-market sale financial

"Sale in open market or private transaction"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

indirect ownership financial

"direct_or_indirect: I, nature_of_ownership: By The Gerald G. Colella 2019 Trust"

Form 4 Insider Transactions: What Each Field Means →

05/28/2026 - 02:04 PM

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

COLELLA GERALD G

(Last)

(First)

(Middle)

C/O MKS INC.

2 TECH DRIVE

(Street)

ANDOVER

MASSACHUSETTS

01810

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MKS INC [ MKSI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/27/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	05/27/2026		S⁽¹⁾		464	D	$330.3828⁽²⁾	39,553	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		8,210	D	$331.4488⁽³⁾	31,343	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		4,876	D	$332.0414⁽⁴⁾	26,467	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		1,811	D	$335.458⁽⁵⁾	24,656	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		1,626	D	$336.5429⁽⁶⁾	23,030	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		213	D	$337.0505⁽⁷⁾	22,817	I	By The Gerald G. Colella 2019 Trust
Common Stock	05/27/2026		S⁽¹⁾		2,800	D	$338.58	20,017	I	By The Gerald G. Colella 2019 Trust
Common Stock								8,998.886	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 24, 2026.

2. This transaction was executed in multiple trades at prices ranging from $329.90 to $330.90. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

3. This transaction was executed in multiple trades at prices ranging from $330.95 to $331.90. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

4. This transaction was executed in multiple trades at prices ranging from $331.98 to $332.44. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

5. This transaction was executed in multiple trades at prices ranging from $334.60 to $335.55. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

6. his transaction was executed in multiple trades at prices ranging from $335.82 to $336.82. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

7. This transaction was executed in multiple trades at prices ranging from $337.00 to $337.73. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

	/s/ M. Kathryn Rickards, attorney-in-fact	05/28/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did MKS Inc (MKSI) report for Gerald G. Colella?

MKS Inc reported that a trust associated with director Gerald G. Colella sold 20,000 shares of common stock. These were open‑market sales on May 27, 2026, disclosed in multiple line items, and left the trust with 39,553 shares afterward.

At what prices were the MKS Inc (MKSI) shares sold by the Colella 2019 Trust?

The Gerald G. Colella 2019 Trust sold MKS Inc common shares at weighted average prices generally in the low $330s per share. Individual reported prices include $338.58, $337.0505, $336.5429, $335.4580, $332.0414, $331.4488, and $330.3828 per share.

How many MKS Inc (MKSI) shares does Gerald G. Colella hold after these transactions?

After the reported transactions, Gerald G. Colella is shown holding 8,998.886 MKS Inc shares directly. The Gerald G. Colella 2019 Trust, reported as an indirect owner, held 39,553 MKS Inc common shares following the series of May 27, 2026 sales.

Were the MKS Inc (MKSI) insider sales by the Colella trust under a Rule 10b5-1 plan?

Yes. A footnote states that one of the transactions was effected pursuant to a Rule 10b5‑1 trading plan adopted by the reporting person on February 24, 2026. Such plans pre‑schedule trades, which can make the timing more routine rather than discretionary.

How many separate sale transactions did the Colella trust execute in MKS Inc (MKSI) stock?

The filing lists seven sale transactions by The Gerald G. Colella 2019 Trust, all coded as open‑market or private sales. Together, they total 20,000 MKS Inc common shares sold on May 27, 2026, according to the transaction summary in the report.

What does the holding entry for 8,998.886 MKS Inc (MKSI) shares represent for Gerald G. Colella?

The entry showing 8,998.886 shares of MKS Inc common stock is classified as a holding with direct ownership. It reflects shares held after the reported date, not a new purchase or sale, and is separate from the indirect holdings of the 2019 Trust.