TransDigm director updates 366,142-share fund stake

Amended Form 4 for TransDigm director Robert J. Small corrects one share in previously reported indirect holdings, with no new market transactions disclosed.

This filing corrects an earlier one, and you can read the original Form 4 if you want to see what changed.

Rhea-AI Filing Summary

TransDigm Group INC (symbol: TDG) is the issuer of record for a Form 4/A filing submitted to the SEC. SMALL ROBERT J reported acquisition or exercise transactions in this Form 4 filing.

TransDigm Group INC director Robert J. Small filed an amended ownership report that records an internal restructuring entry on September 18, 2026 and corrects prior carry-over balances. He now holds 5,677 TransDigm common shares directly, plus 60,246 through family trusts, 366,142 through Stockbridge Fund, L.P., and 68,139 through Stockbridge Partners LLC, with the amendment clarifying that the Stockbridge Fund position is 366,142 shares rather than 366,141.

Insider Trade Summary

Other: 0 shares

Other 4 txns

Insider SMALL ROBERT J

Role Director

Type	Security	Shares	Price	Value
Other	Common Stock	0	$0.00	$0.00
holding	Common Stock	--	--	--
holding	Common Stock F1	--	--	--
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 5,677 shares (Direct); Common Stock — 60,246 shares (Indirect, By Family Trusts); Common Stock — 366,142 shares (Indirect, By Stockbridge Fund, L.P.); Common Stock — 68,139 shares (Indirect, By Stockbridge Partners LLC)

Footnotes (1)

1. F1. Amended to correct the carry-over balance. The reporting person beneficially owns 366,142 shares held by Stockbridge Fund LP, not 366,141 as previously reported.

Key Figures

Direct common shares held: 5,677 shares Indirect shares via family trusts: 60,246 shares Indirect shares via Stockbridge Fund, L.P.: 366,142 shares +2 more

5 metrics

Direct common shares held 5,677 shares Direct TransDigm common stock position after the September 18, 2026 entry

Indirect shares via family trusts 60,246 shares TransDigm common stock held indirectly for Robert J. Small by family trusts

Indirect shares via Stockbridge Fund, L.P. 366,142 shares Corrected beneficial ownership of TransDigm shares through Stockbridge Fund, L.P.

Indirect shares via Stockbridge Partners LLC 68,139 shares TransDigm common stock held indirectly for Robert J. Small by Stockbridge Partners LLC

Corrected prior share difference 1 share Amendment clarifies 366,142 shares, not 366,141, held via Stockbridge Fund, L.P.

Key Terms

beneficially owns, carry-over balance, Family Trusts

3 terms

beneficially owns financial

"The reporting person beneficially owns 366,142 shares held by Stockbridge Fund LP"

Beneficially owns means a person or entity enjoys the economic benefits and control of a security even if the legal title or registration is held in another name. Think of it like having the keys and profits from a car that is registered to a friend: you use it, benefit from it, and make decisions about it even though the official paperwork lists someone else. For investors, this matters because it reveals who truly controls shares, affects voting power, potential conflicts of interest, and regulatory disclosure obligations.

carry-over balance financial

"Amended to correct the carry-over balance"

Family Trusts financial

"Indirect holdings of common stock described as held By Family Trusts"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What does the amended Form 4/A for TDG report about Robert J. Small’s holdings?

It reports that Robert J. Small holds 5,677 TransDigm common shares directly and additional indirect holdings through family trusts and investment entities, with the largest indirect stake of 366,142 shares held by Stockbridge Fund, L.P., as corrected in this amendment.

Did the TDG Form 4/A disclose any new stock purchases or sales by Robert J. Small?

No. The filing shows an internal restructuring-type entry with 0 shares changing hands on September 18, 2026 and focuses on correcting reported balances, rather than disclosing new market purchases or sales of TransDigm stock.

How many TDG shares does Robert J. Small own indirectly through family trusts?

The filing states that 60,246 TransDigm common shares are held indirectly for Robert J. Small through family trusts, in addition to other indirect holdings through investment entities associated with him.

What specific correction does the TDG Form 4/A make for Stockbridge Fund, L.P.?

The amendment explains that Robert J. Small beneficially owns 366,142 shares of TransDigm held by Stockbridge Fund, L.P., correcting an earlier report that showed 366,141 shares as the carry-over balance.

What are Robert J. Small’s reported indirect TDG holdings via Stockbridge Partners LLC?

The filing reports that 68,139 TransDigm common shares are held indirectly for Robert J. Small through Stockbridge Partners LLC, in addition to indirect holdings through family trusts and Stockbridge Fund, L.P.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/22/2026 - 08:24 PM Accepted by SEC EDGAR 09/22/2026 - 08:24 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).

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^*

SMALL ROBERT J

(Last) (First) (Middle)

C/O BERKSHIRE PARTNERS LLC

200 CLARENDON STREET, 35TH FLOOR

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

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)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
09/18/2026

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)
09/21/2026

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	09/18/2026		J		0.00	A	$0.00	5,677	D
Common Stock								60,246	I	By Family Trusts
Common Stock								366,142(1)	I	By Stockbridge Fund, L.P.
Common Stock								68,139	I	By Stockbridge Partners LLC

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

Explanation of Responses:

1. Amended to correct the carry-over balance. The reporting person beneficially owns 366,142 shares held by Stockbridge Fund LP, not 366,141 as previously reported.

Remarks:

	/s/Rachel Quinlan, as attorney in fact for SMALL ROBERT J	09/22/2026
	** 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)