TDG insider ownership: who sold, why, and what they still hold

Who	Shares	Price	% of total stake	Total stake after	Trade date	Filed
Joel Reiss Co-Chief Operating Officer	3,900	$1094.58	52%	3.6K	Sep 15, 2026	Sep 16, 2026

What stands out

Three insiders sold $173M with no disclosed plan: Robert Small ($128M), Nicholas Howley ($40.1M) and Joel Reiss ($5.0M). The filings don't state a reason.Robert Small: largest such sale, Dec 9, 2025 · Nicholas Howley: largest such sale, Jun 18, 2026 · Joel Reiss: largest such sale, Jun 15, 2026

Two insiders bought shares: Michael Lisman (2.9K shares, $3.8M) and Robert Small (1 shares, $1K).Michael Lisman: purchase, Feb 6, 2026 · Robert Small: purchase, Feb 25, 2026

Percentages cover 13 of 18 officers and directors. 5 are left out

Left out: Robert Small (most holdings were last confirmed in 2022); Nicholas Howley (holdings couldn't be fully reconciled); Michael Graff (most holdings were last confirmed in 2019); Armani Vadiee and Irina Krasik (held no vested shares at the start).

Disclosed company stock is not an insider's whole wealth.

Who sold, and how much of their stake

Officers and directors, past 12 months. Each bar is the insider's vested stake at the start of the period (Oct 8, 2025). The gold part is what they sold.

SoldRest of starting stakeAdded during the period

Kevin Stein

Director

Sold 85% of the shares held or received (after tax withholding) during the period†. No bar against the starting stake: most of these shares arrived during the period.

$186MDisclosed plan

Robert Small

Director

No bar: most holdings were last confirmed in 2022.

$128MNo plan disclosed

Nicholas Howley

Director

No bar: holdings couldn't be fully reconciled.

$123M67% planned

Joel Reiss

Co-Chief Operating Officer

Sold 93% of the shares held or received (after tax withholding) during the period†. No bar against the starting stake: most of these shares arrived during the period.

$57.9M91% planned

Patrick Murphy

Co-Chief Operating Officer

Sold 41% of the shares held or received (after tax withholding) during the period†. No bar against the starting stake: most of these shares arrived during the period.

$2.4MDisclosed plan

Amounts, filings and trading plans for each seller

Selling by month

Officers and directors, Oct 2025 to Oct 2026. Each sale is counted once: under a disclosed plan, else to cover taxes, else no plan disclosed.

Disclosed planTo cover taxesNo plan disclosed

Common questions

Is the TransDigm Group CEO selling stock?

No. Michael Lisman reported no open-market sales in the past 12 months.

Why are TransDigm Group insiders selling?

Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 65% of sales by value ran under 10b5-1 trading plans disclosed in the filings and 35% had no disclosed plan. A trading plan schedules sales in advance.

Are any TransDigm Group insiders buying?

Yes. 2 officers or directors reported 8 purchases in the past 12 months (Form 4 code P, which includes private purchases).

How much of their stake did TransDigm Group insiders sell?

About 59% of the shares they held or received (after tax withholding) during the period. The usual measure, against starting holdings alone, can't be used here because most of the shares sold arrived during the period. That covers the 12 months to Oct 8, 2026 and counts vested shares reported on SEC Forms 3, 4 and 5, which is not an insider's whole wealth.

The evidence

Who sold5 officers and directors: amount, % of holdings, trading plan

Who sold	Amount	% of holdings	Trading plan
Kevin Stein Director	$186M 134K shares	85%† i † Most of the shares Kevin Stein sold arrived during the period, so this is shares sold as a share of the 23K held at the start plus the 134K received, less 0 withheld by the company for taxes.	Disclosed plan
Robert Small Director	$128M 96K shares	i No percentage: most holdings were last confirmed in 2022.	No plan disclosed
Nicholas Howley Director	$123M 97K shares	i No percentage: holdings couldn't be fully reconciled.	67% under a disclosed plan
Joel Reiss Co-Chief Operating Officer	$57.9M 46K shares	93%† i † Most of the shares Joel Reiss sold arrived during the period, so this is shares sold as a share of the 3.6K held at the start plus the 46K received, less 0 withheld by the company for taxes.	91% under a disclosed plan
Patrick Murphy Co-Chief Operating Officer	$2.4M 1.7K shares	41%† i † Most of the shares Patrick Murphy sold arrived during the period, so this is shares sold as a share of the 1.1K held at the start plus the 3.2K received, less 0 withheld by the company for taxes.	Disclosed plan

The full ownership picture17 of 18 insiders fully reconciled · 17 officers and directors

Vested shares across all share classes, held directly and through trusts, LLCs and family members, as reported on SEC Forms 3, 4 and 5. Unvested awards and options are never counted as owned shares.

Insider

Held Oct 8, 2025

Sold

Held Oct 8, 2026

Still held

Robert Small

Most of this insider's holdings were last confirmed in 2022. Confirmed in the last three years: 984,836 shares. Not confirmed since: 4,445,389 shares, left out of this row. "Still held" is not shown because it would cover only the smaller, confirmed part.

Director

1.08M

−96K

985K

see note

Vesting, gifts, unvested awards and holding lines for Robert Small

+4.7Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Held through Stockbridge Fund, L.P; the director disclaims ownership beyond their own interest.
Held through Stockbridge Partners LLC; the director disclaims ownership beyond their own interest.
Held through Stockridge Partners LLC; the director disclaims ownership beyond their own interest.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	5,625	5,677
Stockbridge Fund LP	Common Stock	484,632	484,632
Stockbridge Fund, L.P	Common Stock	441,814	366,142
Stockbridge Partners LLC	Common Stock	83,419	68,139
Family Trusts	Common Stock	60,246	60,246

Additional holdings last reported May 23, 2022, not confirmed since: 4,445,389 shares. Not included in any total or percentage on this page.

Berkshire Entities, Common Stock: 4,183,562 shares, last reported Mar 23, 2010
Stockridge Partners LLC, Common Stock: 201,783 shares, last reported Jun 5, 2014
Trust, Common Stock: 31,970 shares, last reported May 23, 2022
Family Trust, Common Stock: 28,074 shares, last reported Sep 28, 2021

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Reconciliation: minor difference of 52 shares. Difference is under 0.5% of holdings.

Nicholas Howley

Holdings couldn't be fully reconciled. Filings report each grant's shares as the balance instead of a running total. See the filing Sales and other transactions for Nicholas Howley are complete.

Director

n/a

−97K

n/a

Vesting, gifts, unvested awards and holding lines for Nicholas Howley

+97Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Holdings couldn't be fully reconciled. Filings report each grant's shares as the balance instead of a running total. The balances below are as reported, not verified totals.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	26,735	239
W. Nicholas Howley Family Trust u/a/d/ 4/23/99	Common Stock	26,734	26,734
W. Nicholas Howely Family Trust u/a/d 4/23/99	Common Stock	23,433	23,433
W. Nicholas Howley Family Trust u/a/d 4/23/99	Common Stock	21,548	21,548
Howley Family Foundation	Common Stock	8,262	8,262

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
518	$1291.97	Nov 4, 2035	$0
116,457	$207.84	Nov 6, 2025	$106M
108,340	$172.84	Nov 6, 2025	$103M
21,419	$172.84	Nov 6, 2025	$20.3M
30,944	$215.92	Nov 10, 2026	$27.9M
105,842	$215.92	Nov 10, 2026	$95.6M
83,954	$140.92	Nov 10, 2026	$82.1M
7,353	$140.92	Nov 10, 2026	$7.2M
1,881	$50.92	Nov 10, 2026	$2.0M
7,908	$50.92	Nov 10, 2026	$8.4M
1,700	$66.47	Nov 8, 2027	$1.8M
21,964	$66.47	Nov 8, 2027	$23.1M
21,964	$66.47	Nov 8, 2027	$23.1M
111,314	$140.92	Nov 10, 2026	$109M

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Sean Hennessy

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.

Director

34K

no sales

Vesting, gifts, unvested awards and holding lines for Sean Hennessy

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	33,749	33,836

Additional holdings last reported Nov 17, 2008, not confirmed since: 655 shares. Not included in any total or percentage on this page.

Direct, Common Stock (restricted): 655 shares, last reported Nov 17, 2008

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

David Barr

New Form 3 filed 2017-10-17; earlier filings set aside.

Director

32K

no sales

Vesting, gifts, unvested awards and holding lines for David Barr

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

New Form 3 filed 2017-10-17; earlier filings set aside.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	32,138	32,225

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Kevin Stein

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.

Director

23K

−134K

23K

not meaningful

Vesting, gifts, unvested awards and holding lines for Kevin Stein

+134Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Fortun Trust dated June 1, 2018	Common Stock	14,972	14,972
Fortuna Trust dated June 1, 2018	Common Stock	8,158	8,158

Additional holdings last reported Dec 31, 2017, not confirmed since: 6,811 shares. Not included in any total or percentage on this page.

Direct, Common Stock (restricted): 6,811 shares, last reported Dec 31, 2017

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
41,800	$869.73	Nov 2, 2033	$10.4M
38,900	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0
163,500	$270.88	Apr 25, 2028	$139M
183,500	$270.88	Apr 25, 2028	$156M
73,500	$195.88	Apr 25, 2028	$67.8M
20,000	$105.88	Apr 25, 2028	$20.3M
17,940	$341.28	Nov 15, 2029	$14.0M
20,000	$342.31	Nov 11, 2030	$15.5M

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Michael Graff

Most of this insider's holdings were last confirmed in 2019. Confirmed in the last three years: 13,813 shares. Not confirmed since: 51,986,715 shares, left out of this row. "Still held" is not shown because it would cover only the smaller, confirmed part.

Director

14K

see note

Vesting, gifts, unvested awards and holding lines for Michael Graff

0shares vested or exercised

−340gifted (net of own trusts)

none reportedunvested awards, start → end

Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	1,993	1,717
trusts	Common Stock	7,000	7,000
Spouse	Common Stock	5,096	5,096

Additional holdings last reported Jul 23, 2019, not confirmed since: 51,986,715 shares. Not included in any total or percentage on this page.

Unresolved (see footnote), Common Stock: 21,351,492 shares, last reported Sep 17, 2007
2012 Carol Ostrow GST Trust, Common Stock: 13,096 shares, last reported Jul 23, 2019
Direct, Common Stock (restricted): 655 shares, last reported Sep 17, 2007
Direct, Common Stock (restricted), par value $0.01 per share: 787 shares, last reported Sep 20, 2010
Direct, Common Stock, par value $0.01 per share: 18,810 shares, last reported Sep 20, 2010
Michael Graff, Common Stock, par value $0.01 per share: 30,601,875 shares, last reported Mar 14, 2006

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
1,760	$231.47	Nov 8, 2027	$1.6M
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Jorge Valladares III

New Form 3 filed 2013-10-10; earlier filings set aside.

Director

11K

no sales

Vesting, gifts, unvested awards and holding lines for Jorge Valladares III

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

New Form 3 filed 2013-10-10; earlier filings set aside.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	11,085	11,085

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
28,080	$559.78	Nov 15, 2029	$15.7M
55,000	$284.97	Nov 8, 2027	$45.9M
61,000	$347.17	Nov 5, 2028	$47.1M
8,500	$476.81	Apr 25, 2029	$5.5M
34,980	$560.81	Nov 11, 2030	$19.5M
13,550	$582.80	Nov 9, 2032	$7.3M
670	$834.73	Nov 2, 2033	$190K
1,773	$226.34	Nov 5, 2025	$1.6M
1,773	$226.34	Nov 5, 2025	$1.6M
1,773	$226.34	Nov 5, 2025	$1.6M

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Peter Palmer

Started reporting during the period; starting holdings are from the Form 3. New Form 3 filed 2025-11-05; earlier filings set aside.

Director

4.1K

no sales

Vesting, gifts, unvested awards and holding lines for Peter Palmer

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Started reporting during the period; starting holdings are from the Form 3.
New Form 3 filed 2025-11-05; earlier filings set aside.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	4,000	4,064

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
17,160	$643.00	Nov 12, 2031	$8.2M
2,600	$582.80	Nov 9, 2032	$1.4M
4,730	$869.73	Nov 2, 2033	$1.2M
22,100	$559.78	Nov 15, 2029	$12.4M
518	$1291.97	Nov 4, 2035	$0
3,000	$476.81	Apr 25, 2029	$1.9M
2,375	$476.81	Apr 25, 2029	$1.5M

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Joel Reiss

New Form 3 filed 2023-06-01; earlier filings set aside.

Co-Chief Operating Officer

3.6K

−46K

3.6K

not meaningful

Vesting, gifts, unvested awards and holding lines for Joel Reiss

+46Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

New Form 3 filed 2023-06-01; earlier filings set aside.

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	3,600	3,600

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
60,300	$226.34	Nov 6, 2025	$53.8M
4,100	$284.97	Nov 8, 2027	$3.4M
31,800	$869.73	Nov 2, 2033	$7.9M
48,300	$226.34	Nov 6, 2025	$43.1M
48,300	$226.34	Nov 6, 2025	$43.1M
15,550	$1302.30	Oct 31, 2034	$0
9,700	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Sarah Wynne

Chief Financial Officer

3.4K

4.9K

no sales

Vesting, gifts, unvested awards and holding lines for Sarah Wynne

+1.5Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	3,400	4,894
Spouse	Common Stock	10	10

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
3,506	$559.78	Nov 15, 2029	$2.0M
47,900	$869.73	Nov 2, 2033	$11.9M
8,200	$1302.30	Oct 31, 2034	$0
8,700	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Michael Lisman

President & CEO, Director

2.3K

5.2K

no sales

Vesting, gifts, unvested awards and holding lines for Michael Lisman

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	2,309	3,259
Michael Lisman Declaration of Trust dated January 31, 2023	Common Stock	0	1,954

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
18,000	$869.73	Nov 2, 2033	$4.5M
23,000	$1059.92	Jan 24, 2034	$1.4M
9,850	$1302.30	Oct 31, 2034	$0
75,696	$1291.97	Nov 4, 2035	$0
3,907	$1291.97	Nov 4, 2035	$0
92,000	$347.17	Nov 5, 2028	$71.0M

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Patrick Murphy

Co-Chief Operating Officer

1.1K

−1.7K

2.5K

not meaningful

Vesting, gifts, unvested awards and holding lines for Patrick Murphy

+3.2Kshares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	1,055	2,515

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
1,450	$347.17	Nov 5, 2028	$1.1M
32,800	$559.78	Nov 15, 2029	$18.3M
21,900	$643.00	Nov 12, 2031	$10.4M
6,500	$582.80	Nov 9, 2032	$3.5M
45,150	$869.73	Nov 2, 2033	$11.3M
26,450	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Gary McCullough

Director

915

993

no sales

Vesting, gifts, unvested awards and holding lines for Gary McCullough

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	915	993

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Michele Santana

Director

741

805

no sales

Vesting, gifts, unvested awards and holding lines for Michele Santana

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	741	805

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Jane Cronin

Director

670

734

no sales

Vesting, gifts, unvested awards and holding lines for Jane Cronin

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	670	734

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
670	$869.73	Nov 2, 2033	$167K
450	$1302.30	Oct 31, 2034	$0
518	$1291.97	Nov 4, 2035	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Jessica Warren

GC, CCO, Secretary

575

no sales

Vesting, gifts, unvested awards and holding lines for Jessica Warren

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	575	575

Stock options (not counted as shares):

Options held	Strike price	Expires	Intrinsic value (estimate)
275	$560.81	Nov 11, 2030	$154K
1,960	$643.00	Nov 12, 2031	$933K
4,150	$869.73	Nov 2, 2033	$1.0M
7,900	$1302.30	Oct 31, 2034	$0

Estimate: options held × ($1118.99 − strike price), using the most recent insider trade price on Form 4 (Sep 15, 2026), not a market close.

Irina Krasik

Director

no sales

Vesting, gifts, unvested awards and holding lines for Irina Krasik

0shares vested or exercised

0gifted (net of own trusts)

none reportedunvested awards, start → end

Held through	Share class	Oct 8, 2025	Oct 8, 2026
Direct	Common Stock	0	13

17 of 18 insiders fully reconciled: starting holdings plus reported transactions match ending holdings (16 exactly, 1 with a minor or footnoted difference). For 1 we show sales but not holdings; the ! icon on that row explains why. Percentages cover 13 of 18 officers and directors. Left out: Robert Small (most holdings were last confirmed in 2022); Nicholas Howley (holdings couldn't be fully reconciled); Michael Graff (most holdings were last confirmed in 2019); Armani Vadiee and Irina Krasik (held no vested shares at the start). "Still held" compares ending with starting vested shares; a plus sign means the holding grew.

What explains the selling$497M of sales by plan status, purpose, seller and month

Officer and director open-market sales: $497M across 373,549 shares. Plan status and stated purpose are separate questions, and a sale can have both.

By plan status

Disclosed plan · $324M · 65%

35%

The lighter segment is sales with no plan disclosed in the filing ($173M), including tax-related sales outside a plan.

No plan disclosed · $173M

Sales with no 10b5-1 plan and no tax reference in the filing. $128M of it is Robert Small. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: Robert Small, Dec 9, 2025

Purchases · 2 buyers (8 trades)

2 officers and directors bought shares in this period, in 8 trades(Form 4 code P). Across all their filings on record there are 441 purchase trades.

Seller	Shares sold	Proceeds	Under a disclosed plan	Share of total	Sales dates
Kevin Stein Director	134K	$186M	100%	38%	Oct 27, 2025 to Feb 2, 2026
Robert Small Director	96K	$128M	0%	26%	Dec 9, 2025 to Dec 10, 2025
Nicholas Howley Director	97K	$123M	67%	25%	Oct 15, 2025 to Aug 18, 2026
Joel Reiss Co-Chief Operating Officer	46K	$57.9M	91%	12%	Oct 20, 2025 to Sep 15, 2026
Patrick Murphy Co-Chief Operating Officer	1.7K	$2.4M	100%	0.5%	Oct 27, 2025 to Feb 2, 2026

Sales by month

Month	Sale proceeds	Disclosed plan	To cover taxes	No plan disclosed
Oct 2025	$9.1M	$9.1M	$0	$0
Nov 2025	$32.9M	$32.9M	$0	$0
Dec 2025	$157M	$29.3M	$0	$128M
Jan 2026	$75.5M	$75.5M	$0	$0
Feb 2026	$87.3M	$87.3M	$0	$0
Mar 2026	$17.1M	$17.1M	$0	$0
Apr 2026	$17.8M	$17.8M	$0	$0
May 2026	$16.5M	$16.5M	$0	$0
Jun 2026	$45.1M	$0	$0	$45.1M
Jul 2026	$17.1M	$17.1M	$0	$0
Aug 2026	$17.4M	$17.4M	$0	$0
Sep 2026	$4.3M	$4.3M	$0	$0
Oct 2026	$0	$0	$0	$0

Is this normal? Selling year by year5 earlier years to compare with

In line with the past 5 years. 5 insiders sold; the average is 9 a year.

12 months ending	Shares sold	Insiders who sold	Proceeds
Oct 8, 2026 Latest 12 months	374K	5	$497M
Oct 8, 2025 1 year earlier	442K	9	$599M
Oct 8, 2024 2 years earlier	844K	11	$952M
Oct 9, 2023 3 years earlier	729K	10	$552M
Oct 9, 2022 4 years earlier	239K	7	$150M
Oct 9, 2021 5 years earlier	395K	7	$240M

Open-market sales (Form 4 code S) by people who were officers or directors, in split-adjusted shares. Earlier years include people who have since left. A sale that an outside holder also reports (a family trust, a fund) is counted with outside holders in every year. Shares, not dollars, are compared, so a change in the stock price doesn't look like a change in selling. Years the filings don't fully cover are shown but left out of the average.

Known gaps and uncertainty1 insider whose holdings couldn't be fully reconciled

Nicholas Howley: holdings couldn't be fully reconciled (difference of -26,735 shares). Filings report each grant's shares as the balance instead of a running total. Filing, Mar 20, 2026

Footnote: "Receipt of stock in lieu of payment of semi-annual director fee, based on fair market value in accordance with the Director Share Plan."

Robert Small: minor difference of 52 shares. Difference is under 0.5% of holdings.

Inferred rename: "In trust" is treated as the same holder as "trusts", because the old name was never reported again and the new one opened with the same balance (4,000 shares). Old name, new name

Inferred rename: "or through certain affiliated investment entities, including direct ownership by Berkshire Fund VII, L.P., Berkshire Fund VII-A, L.P., Berkshire Investors LLC, Berkshire Investors III LLC and Stockbridge Fund, L.P. The Reporting Person disclaims beneficial ownership of the shares except to the extent of his pecuniary interest therein" is treated as the same holder as "Berkshire Entities", because the old name was never reported again and the new one opened with the same balance (4,183,562 shares). Old name, new name

Inferred rename: "managed account" is treated as the same holder as "Stockbridge Partners LLC", because the old name was never reported again and the new one opened with the same balance (103,500 shares). Old name, new name

Inferred rename: "Berkshire Entities" is treated as the same holder as "Stockbridge Fund, L.P", because the old name was never reported again and the new one opened with the same balance (1,001,252 shares). Old name, new name

Inferred typo: the share class "Common Stick" is treated as the same class as "Common Stock" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (Michael Graff, 4,000 shares): old title, new title

External context: we only cite outside events when a documented connection exists. None is shown for this period.

Sources and methodology1,563 filings from SEC EDGAR, and how we read them

All 1,563 Forms 3, 4 and 5 filed for TransDigm Group (SEC CIK 1260221) from Mar 14, 2006 to Sep 22, 2026, retrieved from SEC EDGAR on Oct 8, 2026. Prices are the ones reported in each filing, often weighted averages.

Holdings. Each holding line (a share class plus an owner, such as a trust or LLC) carries its last reported balance forward. Entities first reported during the period start at zero, so transfers between an insider's own trusts don't count as selling. Lines not reported for three years or more are listed separately and left out of totals.

Sales. A sale counts as under a 10b5-1 plan if its footnote cites one or the filing's Rule 10b5-1 box is checked, and as tax-related if its footnote cites tax obligations or sell-to-cover. Shares withheld by the company for taxes are listed separately. Sales with neither attribute are labeled "no plan disclosed".

Full methodology

Former or inactive filers (30)No filing in 18 months; last reported balances, not in any total

Name	Last filed	Last reported balance
John Staer	Mar 14, 2023	117 shares, last reported balance as of Feb 10, 2023
Mervin Dunn	Nov 18, 2022	1,825 shares, last reported balance as of Nov 16, 2022
Raymond Laubenthal	Mar 29, 2022	246,494 shares, last reported balance as of Mar 28, 2022
Robert Henderson	Dec 9, 2021	15,000 shares, last reported balance as of Mar 3, 2021
Halle Terrion	Nov 16, 2021	886 shares, last reported balance as of Nov 24, 2020
Bernt Iversen II	Sep 15, 2020	5,010 shares, last reported balance as of Sep 14, 2020
William Dries	Mar 23, 2020	2,316 shares, last reported balance as of Mar 17, 2020
James Skulina	Oct 11, 2019	33,000 shares, last reported balance as of Oct 10, 2019
Roger Jones	Jun 18, 2018	4,000 shares, last reported balance as of Jun 18, 2018
Terrance Paradie	Apr 4, 2018	2,407 shares, last reported balance as of Apr 2, 2018
Douglas Peacock	Feb 20, 2018	4,574 shares, last reported balance as of Feb 16, 2018
Alex Feil	Feb 12, 2018	3,300 shares, last reported balance as of Feb 9, 2018
Rodrigo Rubiano	Jan 26, 2018	1,070 shares, last reported balance as of Jan 24, 2018
John Leary	Jun 14, 2016	9,260 shares, last reported balance as of Jun 13, 2016
Gregory Rufus	May 11, 2016	12,000 shares, last reported balance as of May 10, 2016
John Tenerowicz	Aug 17, 2015	4,000 shares, last reported balance as of Aug 17, 2015
Sean Maroney	May 18, 2015	200 shares, last reported balance as of May 15, 2015
Michael Borowski	Nov 14, 2014	No balance on record
Vince Ciolli	Nov 14, 2014	No balance on record
Kevin Frailey	Nov 14, 2014	No balance on record
Albert Rodriguez	May 9, 2012	No balance on record
James Riley	Dec 20, 2011	No balance on record
Dudley Sheffler	Sep 22, 2009	1,890 shares, last reported balance as of Sep 22, 2009
TD Group Holdings, LLC	Jun 11, 2009	33,725,914 shares, last reported balance as of Jun 10, 2009
Christopher Anderson	Nov 18, 2008	No balance on record
Ralph McClelland	Mar 13, 2008	500 shares, last reported balance as of Mar 12, 2008
Kevin Kruse	Dec 11, 2007	66,371,508 shares, last reported balance as of Dec 10, 2007
Kewsong Lee	Dec 11, 2007	66,394,577 shares, last reported balance as of Dec 10, 2007
Howard Skurka	Oct 10, 2006	No balance on record
Todd Littleton	Mar 21, 2006	19,868 shares, last reported balance as of Mar 20, 2006

TransDigm Group insiders sold $497M in the past 12 months. How much of their stake is that?

What stands out

Who sold, and how much of their stake

Selling by month

Common questions

Is the TransDigm Group CEO selling stock?

Why are TransDigm Group insiders selling?

Are any TransDigm Group insiders buying?

How much of their stake did TransDigm Group insiders sell?

The evidence

No plan disclosed · $173M

Purchases · 2 buyers (8 trades)

Sales by month