Seagate Technology Holdings STX Insider Ownership

NASDAQ STX

$528.29 -16.85 (-3.09%)

At close: Nov 13, 2026 · 4:00 PM EST

Insider Holdings by Owner

14.38Mn Shares

Holdings, L.P. Valueact13.44Mn93.4%

William D Mosley352.83K2.5%

Stephen J Luczo225.94K1.6%

Gianluca Romano70.76K0.5%

Ravi Naik38.86K0.3%

Other insiders (19)253.95K1.8%

Insider Ownership Statistics

as of 30 Sep, 2026

Insider Ownership

0.280%

▲+0.047% pp QoQ

Shares Held by Insiders

636.09K

filed for Sep 2026

▲+21.48% QoQ

Shares Outstanding

229.71Mn

229,710,441 shares

Direct Holdings

607.46K

Indirect: 28.62K

Net Open-Market Trades

-467.50K

net sold · -$379.11Mn in Sep 2026

Insiders Holding Shares

with Form 4 holdings on file

Shares Owned by Insiders

Shares held % of outstanding

Latest —

Average ownership —

Peak ownership —

Open-Market Insider Trades

Bought Sold

Latest quarter —

Net over range —

Net-buying quarters —

Insider Ownership Summary

Updated Nov 13, 2026

In the last 12 months, insiders at Seagate Technology Holdings made open-market sales of $587.49 million (817.4K shares) and bought no shares on the open market.

A count shows 11 insiders selling STX stock on the open market over the past 12 months and none buying.
William D. Mosley (CEO) sold the most Seagate Technology Holdings stock on the open market over the past 12 months, $316.85 million (459.95K shares), most recently on November 2, 2026.
Beyond open-market trades, insiders at Seagate Technology Holdings acquired 755.34K shares through option exercises and conversions and gave up 37.68K shares to cover taxes or exercise prices in the last 12 months.
According to Business Quant data, insiders at Seagate Technology Holdings reported 615.37K shares in total in their latest Form 4 filings, up 17.52% from 523.63K shares at the end of Q2 2026 and down 23.52% from 804.65K shares at the end of Q3 2025.
Indirect holdings, through trusts, partnerships, family members and other entities, make up 4.65% (28.62K shares) of Seagate Technology Holdings' insider total, with the other 95.35% (586.74K shares) held directly.
Holdings in Seagate Technology Holdings stock are reported by 17 insiders, the officers, directors and 10% owners who have filed a Form 4 in the past two years.
Seagate Technology Holdings' three biggest insider holders are William D. Mosley (CEO, 352.83K shares), Gianluca Romano (EVP & CFO, 70.76K shares) and Richard L. Clemmer (Director, 30.9K shares), based on their latest Form 4 filings.
William D. Mosley alone accounts for 57.34% of the shares held by Seagate Technology Holdings insiders.
Institutions accounted for 83.84% of STX's outstanding shares in Q2 2026.
In the past year, 16 insiders of Seagate Technology Holdings submitted 120 Form 4 filings reporting trades, awards or other transactions.
This summary of Seagate Technology Holdings insider activity covers Form 4 filings through November 3, 2026.

Form 4 Holdings

Insiders Holding STX

Insiders 24

Shares held 14.38Mn

Of outstanding 6.26%

#	Insider	Position	Direct	Indirect	Total	Share of Insiders	Last Filed
1	Holdings, L.P. Valueact	Director, Other	0	13,437,070	13,437,070	93.4%	22 Feb, 2022
2	William D Mosley	Ceo	352,828	0	352,828	2.5%	03 Nov, 2026
3	Stephen J Luczo	Executive Chairman Cob	0	225,941	225,941	1.6%	08 Mar, 2022
4	Gianluca Romano	Evp Cfo	70,757	0	70,757	0.5%	16 Sep, 2026
5	Ravi Naik	Evp, Lyve Storage Services	38,857	0	38,857	0.3%	23 Mar, 2023
6	Richard L Clemmer	Director	30,904	0	30,904	0.2%	26 Oct, 2026
7	Jeffrey D. Nygaard	Evp, Operations And Technology	30,360	0	30,360	0.2%	02 Feb, 2023
8	Katherine Schuelke	Svp, Clo Corporate Secretary	29,063	0	29,063	0.2%	12 Dec, 2023
9	Kian Fatt Chong	Evp Global Operations	25,093	0	25,093	0.2%	16 Sep, 2026
10	John Christopher Morris	Evp Cto	20,933	0	20,933	0.1%	03 Nov, 2026
11	Dylan G. Haggart	Director	15,715	0	15,715	0.1%	26 Oct, 2026
12	Michael R Cannon	Director	14,858	0	14,858	0.1%	26 Oct, 2026
13	Jeffrey D. Fochtman	Svp, Business Marketing	14,736	0	14,736	0.1%	14 Sep, 2022
14	Judy Bruner	Director	0	14,314	14,314	0.1%	21 Oct, 2025
15	Prat Bhatt	Director	14,069	0	14,069	0.1%	26 Oct, 2026
16	Stephanie Tilenius	Director	11,864	0	11,864	0.1%	26 Oct, 2026
17	Shankar Arumugavelu	Director	7,826	0	7,826	0.1%	26 Oct, 2026
18	Robert A Bruggeworth	Director	6,591	0	6,591	0.0%	22 Oct, 2024
19	Ban Seng Teh	Evp Chief Commercial Officer	5,810	0	5,810	0.0%	16 Sep, 2026
20	Yolanda Lee Conyers	Director	4,551	0	4,551	0.0%	26 Oct, 2026
21	Mark Adams	Director	3,246	0	3,246	0.0%	26 Oct, 2026
22	Thomas A Szlosek	Director	1,558	0	1,558	0.0%	26 Oct, 2026
23	Jay L Geldmacher	Director	1,423	0	1,423	0.0%	26 Oct, 2026
24	James Ci Lee	Evp Clo	1,037	0	1,037	0.0%	26 Oct, 2026

Each row is that insider’s most recently reported position, from Form 4 filings over the last 60 months — which is why this total does not tie to the quarterly series above, where a quarter counts only the insiders who filed in it. Shares held through a fund or institutional portfolio are counted on the institutional ownership page instead.

Form 4 Filings

6,234 Insider Transactions

Source SEC Form 4

Latest quarter Sep 2026

Date	Insider	Position	Transaction	Shares	Price	Value	Shares Held After	Ownership
30 Oct, 2026	John Christopher Morris	Evp Cto	Acquired M	915	$158.40	$144.94K	23,608	Direct
02 Nov, 2026	William D Mosley	Ceo	Acquired M	14,000	$46.23	$647.22K	376,108	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	960	$617.67	$592.96K	351,868	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	720	$587.99	$423.35K	375,388	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	760	$618.80	$470.29K	351,108	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	80	$626.41	$50.11K	23,528	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	40	$628.28	$25.13K	23,488	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	600	$589.27	$353.56K	374,788	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	1,160	$619.60	$718.73K	349,948	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	800	$590.40	$472.32K	373,988	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	82	$630.19	$51.68K	23,406	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	720	$620.80	$446.98K	349,228	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	1,080	$621.89	$671.65K	348,148	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	118	$631.69	$74.54K	23,288	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	280	$591.23	$165.54K	373,708	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	160	$633.22	$101.32K	23,128	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	1,400	$592.71	$829.79K	372,308	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	240	$623.01	$149.52K	347,908	Direct
30 Oct, 2026	John Christopher Morris	Evp Cto	Disposed S	80	$635.54	$50.84K	23,048	Direct
02 Nov, 2026	William D Mosley	Ceo	Disposed S	1,639	$593.47	$972.69K	370,669	Direct

Showing 1 to 20 of 6,234 transactions