[Form 4] TransDigm Group INC Insider Trading Activity

TransDigm Group director Kevin M. Stein, through the Fortuna Trust dated June 1, 2018, reported an option exercise and related stock sales.

Rhea-AI Filing Summary

TransDigm Group director Kevin M. Stein, through the Fortuna Trust dated June 1, 2018, reported an option exercise and related stock sales. On January 8, 2026, the trust exercised a stock option for 17,373 shares of common stock at an exercise price of $342.31 per share, with the price adjusted for dividends declared since August 1, 2022. The same day, the trust sold a total of 17,373 TransDigm Group shares in several market transactions at average prices ranging from about $1,405.3006 to $1,413.17 per share. After these transactions, the trust held 8,158 shares of TransDigm common stock and 50,627 stock options, all reported as indirectly owned.

Insider Trade Summary

Exercise and Sale: 17,373 shares ($18.50M approx. pre-tax spread)

Exercise and Sale 9 txns

Insider Stein Kevin M

Role Director

Sold 17,373 shs ($24.45M)

Approx. gross sale proceeds $24.45M

Approx. exercise cost $5.95M

Approx. pre-tax spread $18.50M

Type	Security	Shares	Price	Value
Exercise	Stock Option.	17,373	$0.00	$0.00
Exercise	Common Stock	17,373	$342.31	$5.95M
Sale	Common Stock	6,384	$1,405.3006	$8.97M
Sale	Common Stock	1,278	$1,406.7156	$1.80M
Sale	Common Stock	2,722	$1,407.4564	$3.83M
Sale	Common Stock	5,239	$1,408.4395	$7.38M
Sale	Common Stock	480	$1,409.5663	$677K
Sale	Common Stock	930	$1,410.6495	$1.31M
Sale	Common Stock	340	$1,413.17	$480K

Holdings After Transaction: Stock Option. — 50,627 contracts (Indirect, Fortuna Trust dated June 1, 2018); Common Stock — 8,158 shares (Indirect, Fortuna Trust dated June 1, 2018)

Footnotes (7)

1. F1. The exercise price has been adjusted for dividends declared since August 1, 2022.
2. F2. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,405.0000 - $1,405.9900. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
3. F3. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,406.0000 - $1,406.9950. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
4. F4. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,407.0000 - $1,407.9150. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
5. F5. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,408.1500 - $1,409.1100. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
6. F6. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,409.1600 - $1,410.0800. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.
7. F7. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,410.4600 - $1,411.4350. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

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Accepted by SEC EDGAR 01/09/2026 - 04:25 PM Learn about SEC filing dates

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).

X

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^*

Stein Kevin M

(Last) (First) (Middle)

1350 EUCLID AVE

SUITE 1600

(Street)

CLEVELAND OH 44115

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
TransDigm Group INC [ TDG ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
01/08/2026

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

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

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

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)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/08/2026		M		17,373	A	$342.31(1)	25,531	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		6,384	D	$1,405.3006(2)	19,147	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		1,278	D	$1,406.7156(3)	17,869	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		2,722	D	$1,407.4564(4)	15,147	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		5,239	D	$1,408.4395(5)	9,908	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		480	D	$1,409.5663(6)	9,428	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		930	D	$1,410.6495(7)	8,498	I	Fortuna Trust dated June 1, 2018
Common Stock	01/08/2026		S		340	D	$1,413.17	8,158	I	Fortuna Trust dated June 1, 2018

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)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option.	$342.31(1)	01/08/2026		M			17,373	09/30/2025	11/11/2030	Common Stock	17,373	$0	50,627	I	Fortuna Trust dated June 1, 2018

Explanation of Responses:

1. The exercise price has been adjusted for dividends declared since August 1, 2022.

2. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,405.0000 - $1,405.9900. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

3. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,406.0000 - $1,406.9950. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

4. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,407.0000 - $1,407.9150. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

5. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,408.1500 - $1,409.1100. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

6. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,409.1600 - $1,410.0800. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

7. Price reported constitutes the average weighted price of shares sold. Shares were sold at varying prices in the range of $1,410.4600 - $1,411.4350. The reporting person hereby undertakes, upon request of the Commission, the issuer or a security holder of the issuer, to provide full information regarding the number of shares sold at each separate price.

	/s/ Rachel Quinlan as attorney in fact for Kevin Stein	01/09/2026
	** 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).
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