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STXSeagate Technology · Insider ownership research

Seagate Technology insiders sold $595M in the past 12 months. How much of their stake is that?

About 9.9% overall. As a group they ended with more shares than they started with. These figures leave out William Mosley, the largest holder (most of their shares vested during the period, so a percentage would mislead).

Updated Oct 9, 2026 from SEC filings · covers Oct 10, 2025 to Oct 9, 2026
How this comparesMore of their stake sold than at 286 of the 416 other companies we can measure (#131 of 417)See ranking
0
buyers among officers and directors, past 12 months
66%
of sales were under disclosed trading plans, past 12 months
11 of 16
officers and directors sold shares, past 12 months
Recent activity · past 30 days, Sep 10, 2026 to Oct 9, 2026
Oct 1, 2026William Mosley sold 30K shares ($27.7M) under a disclosed trading plan. That is 7.7% of the total stake held that day. 14K shares came in from vesting or option exercises the same day, so the holding fell by 16K net.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
William Mosley
CEO, Director
30,000$922.35 avg7.7%362KOct 1, 2026Oct 2, 2026 +1 more

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 21, 2026John Morris sold 9.4K shares ($8.2M) under a disclosed trading plan. That is 29% of the total stake held that day. 915 shares came in from vesting or option exercises the same day, so the holding fell by 8.4K net.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
John Morris
EVP & CTO
9,354$877.9129%23KSep 21, 2026Sep 22, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 15, 20263 executives sold 163K shares ($126M) to cover taxes on vesting stock. That is between 21% and 41% of each person's total stake held that day.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
William Mosley
CEO, Director
97,889$772.1421%378KSep 15, 2026Sep 16, 2026
Gianluca Romano
EVP & CFO
49,984$772.1641%71KSep 15, 2026Sep 16, 2026
John Morris
EVP & CTO
15,466$772.1533%31KSep 15, 2026Sep 16, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 15, 2026Ban Teh sold 53K shares ($41.2M) under a disclosed trading plan. That is 90% of the total stake held that day.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Ban Teh
EVP & Chief Commercial Officer
52,730$782.0890%5.6KSep 15, 2026Sep 16, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 14, 20263 executives sold 3.3K shares ($2.6M) to cover taxes on vesting stock. That is between 0.4% and 1.0% of each person's total stake held that day. 298K shares came in from vesting or option exercises the same day, so their combined holdings rose by 294K net.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
William Mosley
CEO, Director
1,870$781.230.4%476KSep 14, 2026Sep 15, 2026
Gianluca Romano
EVP & CFO
Also under a disclosed plan
955$781.240.8%121KSep 14, 2026Sep 15, 2026
John Morris
EVP & CTO
493$781.231.0%46KSep 14, 2026Sep 15, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 14, 2026Ban Teh sold 989 shares ($770K) under a disclosed trading plan. That is 1.7% of the total stake held that day. 53K shares came in from vesting or option exercises the same day, so the holding rose by 52K net.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Ban Teh
EVP & Chief Commercial Officer
989$779.001.7%58KSep 14, 2026Sep 15, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 11, 2026Gianluca Romano sold 50K shares ($42.0M) under a disclosed trading plan. That is 62% of the total stake held that day. 52K shares came in from vesting or option exercises the same day, so the holding rose by 1.7K net.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Gianluca Romano
EVP & CFO
50,498$832.25 avg62%31KSep 11, 2026Sep 15, 2026 +1 more

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 10, 20263 executives sold 4.8K shares ($4.1M) with no plan disclosed. That is between 0.9% and 4.4% of each person's total stake held that day.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
William Mosley
CEO, Director
2,849$862.130.9%297KSep 10, 2026Sep 11, 2026
Gianluca Romano
EVP & CFO
1,348$862.134.4%29KSep 10, 2026Sep 11, 2026
John Morris
EVP & CTO
572$862.133.5%16KSep 10, 2026Sep 11, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Sep 10, 2026Ban Teh sold 663 shares ($570K) under a disclosed trading plan. That is 11% of the total stake held that day.
WhoSharesPrice% of total stakeTotal stake afterTrade dateFiled
Ban Teh
EVP & Chief Commercial Officer
663$860.0911%5.6KSep 10, 2026Sep 11, 2026

"% of total stake" is the shares in this event against all the vested shares the person held that day, across every share class and holding entity, after that day's vesting. "n/a" means the person's holdings don't reconcile, or the row is a purchase. "Holdings record incomplete" means more shares were sold than the filings show the person held that day, so a percentage would be wrong.

Is this normal? More than usual: about 1.6x the 5-year average. 11 insiders sold; the average is 9 a year. Year by year
Latest filing: Filed Oct 2 for a sale on Oct 1. William Mosley sold 19K shares ($17.4M) under a disclosed plan. Filing
137 SEC ownership filings in the period · See the evidence

What stands out

Two directors sold more than 25% of vested holdings: Shankar Arumugavelu (57% of holdings, $2.4M, none under a disclosed plan) and Stephanie Tilenius (30% of holdings, $1.8M, none under a disclosed plan).Shankar Arumugavelu: largest sale, Nov 10, 2025 · Stephanie Tilenius: largest sale, May 5, 2026
Five officers sold $67.6M with no disclosed plan: William Mosley ($31.8M), Ban Teh ($17.3M) and Gianluca Romano ($10.8M), plus 2 more. The filings don't state a reason.William Mosley: largest such sale, Mar 19, 2026 · Ban Teh: largest such sale, Aug 13, 2026 · Gianluca Romano: largest such sale, Aug 21, 2026
Selling picked up in the last 90 days: officers and directors sold 468K shares, against an average of 136K per 90 days earlier in the period. Most of it was William Mosley (211K shares in the last 90 days) and Gianluca Romano (134K shares in the last 90 days); 56% of these sales were under disclosed plans.William Mosley: largest recent sale, Sep 15, 2026 · Gianluca Romano: largest recent sale, Sep 15, 2026

Percentages cover 6 of 16 officers and directors. 10 are left out

i
Left out: William Mosley, Gianluca Romano, Ban Teh, John Morris, Kian Chong, Yolanda Conyers, Jay Geldmacher and James Lee (most of their shares vested during the period, so a percentage would mislead); Mark Adams and Thomas Szlosek (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 100% of that person's own stake; not comparable between people. The stake is the vested shares held at the start of the period (Oct 9, 2025); the gold part is what they sold.

William Mosley
CEO, Director
Sold $304M (plan status beside the amount). That is 55% of the shares held or received (after tax withholding) during the period†. A share of the starting stake is not shown: most of these shares arrived during the period. Why
$304M64% planned, 25% to cover taxes 10% no plan disclosed
Gianluca Romano
EVP & CFO
Sold $146M (plan status beside the amount). That is 76% of the shares held or received (after tax withholding) during the period†. A share of the starting stake is not shown: most of these shares arrived during the period. Why
$146M66% planned, 26% to cover taxes 7% no plan disclosed
Ban Teh
EVP & Chief Commercial Officer
Sold $89.3M (plan status beside the amount). That is 96% of the shares held or received (after tax withholding) during the period†. A share of the starting stake is not shown: most of these shares arrived during the period. Why
$89.3M81% planned 19% no plan disclosed
John Morris
EVP & CTO
Sold $30.6M (plan status beside the amount). That is 63% of the shares held or received (after tax withholding) during the period†. A share of the starting stake is not shown: most of these shares arrived during the period. Why
$30.6M57% planned, 40% to cover taxes 3% no plan disclosed
James Lee
EVP & CLO
Sold $12.6M (plan status beside the amount). That is 98% of the shares held or received (after tax withholding) during the period†. A share of the starting stake is not shown: most of these shares arrived during the period. Why
$12.6M69% planned, 4% to cover taxes 27% no plan disclosed
All 11 sellers

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 disclosedOne dollar scale for every month; the tallest bar is labeled
Oct 2025: $318K under a disclosed planOct 2025: $2.3M no plan disclosedOctNov 2025: $23.4M under a disclosed planNov 2025: $3.6M no plan disclosedNovDec 2025: $6.3M under a disclosed planDecJan 2026: $6.4M under a disclosed planJan 2026: $9.3M no plan disclosedJanFeb 2026: $8.7M under a disclosed planFeb 2026: $2.4M no plan disclosedFebMar 2026: $8.0M under a disclosed planMar 2026: $10.0M no plan disclosedMarApr 2026: $8.4M under a disclosed planAprMay 2026: $58.8M under a disclosed planMay 2026: $1.2M no plan disclosedMayJun 2026: $31.6M under a disclosed planJun 2026: $7.2M no plan disclosedJunJul 2026: $28.1M under a disclosed planJul 2026: $491K to cover taxesJulAug 2026: $66.6M under a disclosed planAug 2026: $33.2M no plan disclosedAugSep 2026: $119M under a disclosed planSep 2026: $128M to cover taxesSep 2026: $4.1M no plan disclosed$251MSepOct 2026: $27.7M under a disclosed planOct

Outside holders, reported separately

ValueAct Holdings, L.P. reported no open-market sales in the past 12 months. Large shareholders and the funds or companies that board members represent are not part of management, so they are left out of the figures above.

Details

Common questions

Is the Seagate Technology CEO selling stock?

Yes. William Mosley sold 450K shares ($304M) in the past 12 months, 64% of it under a trading plan disclosed in the filings.

Why are Seagate Technology insiders selling?

Filings rarely give a reason, and we don't guess at one. What they show is how the sales were made: 66% of sales by value ran under 10b5-1 trading plans disclosed in the filings, 22% were to cover taxes and 12% had no disclosed plan. A trading plan schedules sales in advance.

Are any Seagate Technology insiders buying?

No. Officers and directors reported no purchases in the past 12 months.

How much of their stake did Seagate Technology insiders sell?

About 9.9% overall. As a group they ended with more shares than they started with. These figures leave out William Mosley, the largest holder (most of their shares vested during the period, so a percentage would mislead). That covers the 12 months to Oct 9, 2026 and counts vested shares reported on SEC Forms 3, 4 and 5, which is not an insider's whole wealth.

The evidence

Who sold11 officers and directors: amount, % of holdings, trading plan
Who soldAmount% of holdingsTrading plan
William Mosley
CEO, Director
$304M
450K shares
55%†
i
† Most of the shares William Mosley sold arrived during the period, so this is shares sold as a share of the 486K held at the start plus the 341K received, less 15K withheld by the company for taxes.
64% under a disclosed plan, 25% to cover taxes 10% no plan disclosed
Gianluca Romano
EVP & CFO
$146M
223K shares
76%†
i
† Most of the shares Gianluca Romano sold arrived during the period, so this is shares sold as a share of the 58K held at the start plus the 253K received, less 17K withheld by the company for taxes.
66% under a disclosed plan, 26% to cover taxes 7% no plan disclosed
Ban Teh
EVP & Chief Commercial Officer
$89.3M
127K shares
96%†
i
† Most of the shares Ban Teh sold arrived during the period, so this is shares sold as a share of the 18K held at the start plus the 115K received, less 0 withheld by the company for taxes.
81% under a disclosed plan 19% no plan disclosed
John Morris
EVP & CTO
$30.6M
38K shares
63%†
i
† Most of the shares John Morris sold arrived during the period, so this is shares sold as a share of the 13K held at the start plus the 51K received, less 3.9K withheld by the company for taxes.
57% under a disclosed plan, 40% to cover taxes 3% no plan disclosed
James Lee
EVP & CLO
$12.6M
16K shares
98%†
i
† Most of the shares James Lee sold arrived during the period, so this is shares sold as a share of the 257 held at the start plus the 18K received, less 1.6K withheld by the company for taxes.
69% under a disclosed plan, 4% to cover taxes 27% no plan disclosed
Kian Chong
EVP Global Operations
$4.4M
13K shares
34%†
i
† Most of the shares Kian Chong sold arrived during the period, so this is shares sold as a share of the 7.1K held at the start plus the 31K received, less 0 withheld by the company for taxes.
No plan disclosed
Shankar Arumugavelu
Director
$2.4M
6K shares
57%No plan disclosed
Yolanda Conyers
Director
$1.8M
3K shares
47%†
i
† Most of the shares Yolanda Conyers sold arrived during the period, so this is shares sold as a share of the 4.3K held at the start plus the 2.7K received, less 647 withheld by the company for taxes.
Disclosed plan
Stephanie Tilenius
Director
$1.8M
3.6K shares
30%No plan disclosed
Prat Bhatt
Director
$930K
1K shares
8.5%Disclosed plan
Jay Geldmacher
Director
$751K
2.2K shares
91%†
i
† Most of the shares Jay Geldmacher sold arrived during the period, so this is shares sold as a share of the 352 held at the start plus the 2.7K received, less 647 withheld by the company for taxes.
No plan disclosed

Outside holder, reported separately: ValueAct Holdings, L.P. (an outside shareholder, not part of management). No open-market sales reported in the period. Holds 15K shares. Latest filing

The full ownership picture16 of 16 insiders fully reconciled · 16 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.

InsiderHeld Oct 9, 2025SoldHeld Oct 9, 2026Still held
William Mosley
i
Minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer). Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
CEO, Director
486K−450K362Knot meaningful
Vesting, gifts, unvested awards and holding lines for William Mosley
+341Kshares vested or exercised
0gifted (net of own trusts)
−15Kwithheld by the company for taxes
251K → 196Kunvested awards, start → end
  • Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares485,668362,108

Additional holdings last reported Sep 13, 2010, not confirmed since: 57,845 shares. Not included in any total or percentage on this page.

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
104,347$54.78Sep 9, 2026$93.0M
153,700$158.40Aug 20, 2032$121M
31,856$850.24Aug 20, 2033$3.0M

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Gianluca Romano
i
Minor difference of 134 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
EVP & CFO
58K−223K71Knot meaningful
Vesting, gifts, unvested awards and holding lines for Gianluca Romano
+253Kshares vested or exercised
0gifted (net of own trusts)
−17Kwithheld by the company for taxes
138K → 97Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares57,78570,757

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
40,317$158.40Aug 20, 2032$31.8M
11,360$850.24n/a$1.1M

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 134 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Richard Clemmer
Director
32K034Kno sales
Vesting, gifts, unvested awards and holding lines for Richard Clemmer
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares27,65829,704
SpouseOrdinary Shares3,8673,867
Michael Cannon
i
Includes unvested RSUs, amount not disclosed. Additional holdings last reported more than 3 years ago are shown separately and excluded from totals. New Form 3 filed 2011-02-01; earlier filings set aside.
Director
25K027Kno sales
Vesting, gifts, unvested awards and holding lines for Michael Cannon
+3.4Kshares vested or exercised
0gifted (net of own trusts)
−823withheld by the company for taxes
3.4K → 1.9Kunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
  • Additional holdings last reported more than 3 years ago are shown separately and excluded from totals.
  • New Form 3 filed 2011-02-01; earlier filings set aside.
Held throughShare classOct 9, 2025Oct 9, 2026
Direct
includes unvested RSUs, amount not disclosed
Ordinary Shares10,83513,439
Michael R. Cannon TrustOrdinary Shares6,8856,885
Cannon TrustOrdinary Shares6,8856,885

Additional holdings last reported Oct 24, 2012, not confirmed since: 6,885 shares. Not included in any total or percentage on this page.

Ban Teh
i
Minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
EVP & Chief Commercial Officer
18K−127K5.8Knot meaningful
Vesting, gifts, unvested awards and holding lines for Ban Teh
+115Kshares vested or exercised
0gifted (net of own trusts)
71K → 54Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares18,0415,810

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
18,144$158.40Aug 20, 2032$14.3M
4,736$850.24Aug 20, 2033$453K

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Judy Bruner
Director
17K019Kno sales
Vesting, gifts, unvested awards and holding lines for Judy Bruner
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 0unvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares4,2714,271
Bruner Living TrustOrdinary Shares12,26814,314
John Morris
i
Minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
EVP & CTO
13K−38K23Knot meaningful
Vesting, gifts, unvested awards and holding lines for John Morris
+51Kshares vested or exercised
0gifted (net of own trusts)
−3.9Kwithheld by the company for taxes
60K → 49Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares13,23822,693

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
17,378$158.40Aug 20, 2032$13.7M
6,152$850.24Aug 20, 2033$589K

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Stephanie Tilenius
i
Includes unvested RSUs, amount not disclosed.
Director
12K−3.6K11K87%
Vesting, gifts, unvested awards and holding lines for Stephanie Tilenius
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
Held throughShare classOct 9, 2025Oct 9, 2026
Direct
includes unvested RSUs, amount not disclosed
Ordinary Shares12,24410,664
Prat Bhatt
Director
12K−1K13K+8.9%
Vesting, gifts, unvested awards and holding lines for Prat Bhatt
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares11,82312,869
Shankar Arumugavelu
Director
11K−6K6.6K63%
Vesting, gifts, unvested awards and holding lines for Shankar Arumugavelu
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares10,5806,626
Kian Chong
i
Minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
EVP Global Operations
7.1K−13K25Knot meaningful
Vesting, gifts, unvested awards and holding lines for Kian Chong
+31Kshares vested or exercised
0gifted (net of own trusts)
40K → 31Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares7,07825,093

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
13,976$158.40Aug 20, 2032$11.0M
3,788$850.24Aug 20, 2033$363K

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Yolanda Conyers
Director
4.3K−3K3.4Knot meaningful
Vesting, gifts, unvested awards and holding lines for Yolanda Conyers
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares4,3053,351
Jay Geldmacher
i
Includes unvested RSUs, amount not disclosed.
Director
352−2.2K223not meaningful
Vesting, gifts, unvested awards and holding lines for Jay Geldmacher
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 1.6Kunvested awards, start → end
  • Includes unvested RSUs, amount not disclosed.
Held throughShare classOct 9, 2025Oct 9, 2026
Direct
includes unvested RSUs, amount not disclosed
Ordinary Shares352223
James Lee
i
Minor difference of 89 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).
EVP & CLO
257−16K347not meaningful
Vesting, gifts, unvested awards and holding lines for James Lee
+18Kshares vested or exercised
0gifted (net of own trusts)
−1.6Kwithheld by the company for taxes
28K → 18Kunvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares257347

Stock options (not counted as shares):

Options heldStrike priceExpiresIntrinsic value (estimate)
12,096$158.40Aug 20, 2032$9.5M

Estimate: options held × ($945.97 − strike price), using the most recent insider trade price on Form 4 (Oct 1, 2026), not a market close.

Reconciliation: minor difference of 89 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Mark Adams
i
New Form 3 filed 2024-10-22; earlier filings set aside.
Director
002Kno sales
Vesting, gifts, unvested awards and holding lines for Mark Adams
+2.7Kshares vested or exercised
0gifted (net of own trusts)
−647withheld by the company for taxes
2.7K → 4.3Kunvested awards, start → end
  • New Form 3 filed 2024-10-22; earlier filings set aside.
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares02,046
Thomas Szlosek
Director
00357no sales
Vesting, gifts, unvested awards and holding lines for Thomas Szlosek
+470shares vested or exercised
0gifted (net of own trusts)
−113withheld by the company for taxes
470 → 0unvested awards, start → end
Held throughShare classOct 9, 2025Oct 9, 2026
DirectOrdinary Shares0357

16 of 16 insiders fully reconciled: starting holdings plus reported transactions match ending holdings (10 exactly, 6 with a minor or footnoted difference). Percentages cover 6 of 16 officers and directors. Left out: William Mosley, Gianluca Romano, Ban Teh, John Morris, Kian Chong, Yolanda Conyers, Jay Geldmacher and James Lee (most of their shares vested during the period, so a percentage would mislead); Mark Adams and Thomas Szlosek (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$595M of sales by plan status, purpose, seller and month

Officer and director open-market sales: $595M across 883,096 shares. Plan status and stated purpose are separate questions, and a sale can have both.

By plan status

The lighter segment is sales with no plan disclosed in the filing ($202M), including tax-related sales outside a plan.

No plan disclosed · $73.4M

Sales with no 10b5-1 plan and no tax reference in the filing. $31.8M of it is William Mosley. No plan disclosed is a statement about the filing, not about why the sale happened. Largest such sale: William Mosley, Mar 19, 2026

Taxes

$129M of sales (21.7%) cite tax obligations in their footnotes, $746K of them also under a plan. Separately, 43,501 shares ($15.6M) were withheld by the company for taxes, which isn't a market sale. Example: John Morris, Sep 15, 2026

SellerShares soldProceedsUnder a disclosed planShare of totalSales dates
William Mosley
CEO, Director
450K$304M64%51%Nov 3, 2025 to Oct 1, 2026
Gianluca Romano
EVP & CFO
223K$146M66%25%Nov 12, 2025 to Sep 15, 2026
Ban Teh
EVP & Chief Commercial Officer
127K$89.3M81%15%Oct 13, 2025 to Sep 15, 2026
John Morris
EVP & CTO
38K$30.6M57%5%Dec 15, 2025 to Sep 21, 2026
James Lee
EVP & CLO
16K$12.6M69%2%Nov 11, 2025 to Aug 24, 2026
Kian Chong
EVP Global Operations
13K$4.4M0%0.7%Oct 30, 2025 to Feb 23, 2026
Shankar Arumugavelu
Director
6K$2.4M0%0.4%Nov 10, 2025 to Jun 4, 2026
Yolanda Conyers
Director
3K$1.8M100%0.3%Dec 2, 2025 to Sep 1, 2026
Stephanie Tilenius
Director
3.6K$1.8M0%0.3%Nov 3, 2025 to May 5, 2026
Prat Bhatt
Director
1K$930K100%0.2%Jun 2, 2026 to Jun 2, 2026
Jay Geldmacher
Director
2.2K$751K0%0.1%Oct 31, 2025 to Jan 30, 2026

Sales by month

MonthSale proceedsDisclosed planTo cover taxesNo plan disclosed
Oct 2025$2.6M$318K$0$2.3M
Nov 2025$27.0M$23.4M$0$3.6M
Dec 2025$6.3M$6.3M$0$0
Jan 2026$15.7M$6.4M$0$9.3M
Feb 2026$11.1M$8.7M$0$2.4M
Mar 2026$18.0M$8.0M$0$10.0M
Apr 2026$8.4M$8.4M$0$0
May 2026$60.0M$58.8M$0$1.2M
Jun 2026$38.8M$31.6M$0$7.2M
Jul 2026$28.5M$28.1M$491K$0
Aug 2026$99.8M$66.6M$0$33.2M
Sep 2026$251M$119M$128M$4.1M
Oct 2026$27.7M$27.7M$0$0
Is this normal? Selling year by year5 earlier years to compare with

More than usual: about 1.6x the 5-year average. 11 insiders sold; the average is 9 a year.

12 months endingShares soldInsiders who soldProceeds
Oct 9, 2026
Latest 12 months
883K11$595M
Oct 9, 2025
1 year earlier
704K11$87.1M
Oct 9, 2024
2 years earlier
575K9$53.3M
Oct 10, 2023
3 years earlier
349K3$24.7M
Oct 10, 2022
4 years earlier
122K8$12.5M
Oct 10, 2021
5 years earlier
1.07M12$85.7M

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 uncertaintyEvery officer and director reconciles

Every officer and director reconciles for this period.

William Mosley: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Gianluca Romano: minor difference of 134 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Ban Teh: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

John Morris: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Kian Chong: minor difference of 161 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

James Lee: minor difference of 89 shares. Difference is stated in footnotes (unreported vesting, exempt acquisition or transfer).

Inferred rename: "Dexheimer Retained Annuity Trust" is treated as the same holder as "Dexheimer Grantor Retained Annuity Trust", because the old name was never reported again and the new one opened with the same balance (60,000 shares). Old name, new name

Inferred rename: "Silver Sea Limited Partnership" is treated as the same holder as "Silver Seas Partnership", because the old name was never reported again and the new one opened with the same balance (161,664 shares). Old name, new name

Inferred rename: "See Explanation of Responses (1) (2)" is treated as the same holder as "See Explanation of Responses", because the old name was never reported again and the new one opened with the same balance (847,500,000 shares). Old name, new name

Inferred rename: "0" is treated as the same holder as "New SAC", because the old name was never reported again and the new one opened with the same balance (847,500,000 shares). Old name, new name

Inferred rename: "Silver Lake Funds and those previously held by New SAC" is treated as the same holder as "Silver Lake Funds", because the old name was never reported again and the new one opened with the same balance (31,811,080 shares). Old name, new name

Inferred rename: "Zander Living Trust" is treated as the same holder as "Edward and Mona Zander Living Trus", because the old name was never reported again and the new one opened with the same balance (8,750 shares). Old name, new name

Inferred rename: "Edward and Mona Zander Living Trus" is treated as the same holder as "Edward and Mona Zander Living Trust", because the old name was never reported again and the new one opened with the same balance (30,448 shares). Old name, new name

Inferred rename: "0" is treated as the same holder as "New SAC", because the old name was never reported again and the new one opened with the same balance (847,500,000 shares). Old name, new name

Inferred rename: "Member of the Board New SAC" is treated as the same holder as "Member of the Board of New SAC", because the old name was never reported again and the new one opened with the same balance (847,500,000 shares). Old name, new name

Inferred rename: "Wolf Pack Limited Partnership" is treated as the same holder as "Wolf PackLimited Partnership", because the old name was never reported again and the new one opened with the same balance (126,046 shares). Old name, new name

Inferred rename: "Ltephen J. Luczo Revocable Trust dated January 26, 2001" is treated as the same holder as "tephen J. Luczo Revocable Trust dated January 26, 2001", because the old name was never reported again and the new one opened with the same balance (4,906,785 shares). Old name, new name

Inferred rename: "Red Zone II Limited Partnership" is treated as the same holder as "Red Zone Holdings II Limited Partnership", because the old name was never reported again and the new one opened with the same balance (150,000 shares). Old name, new name

Inferred rename: "Silver Lake Funds and those previously held by New SAC" is treated as the same holder as "Silver Lake Funds", because the old name was never reported again and the new one opened with the same balance (31,811,080 shares). Old name, new name

Inferred rename: "Trust" is treated as the same holder as "Pope Family Trust", because the old name was never reported again and the new one opened with the same balance (1,500 shares). Old name, new name

Inferred rename: "Waite Family Trust dated 12/21/1989" is treated as the same holder as "Family Trust", because the old name was never reported again and the new one opened with the same balance (403,152 shares). Old name, new name

Inferred rename: "Tennenbaum Anuuity Trust" is treated as the same holder as "Tennenbaum Annutiy Trust", because the old name was never reported again and the new one opened with the same balance (75,000 shares). Old name, new name

Inferred rename: "Tennenbaum Annutiy Trust" is treated as the same holder as "Tennenbaum Annuity Trust", because the old name was never reported again and the new one opened with the same balance (72,300 shares). Old name, new name

Inferred typo: the share class "Common Sahres" is treated as the same class as "Common Shares" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (Stephen Luczo, 972 shares): old title, new title

Inferred typo: the share class "Coomon Shares" is treated as the same class as "Common Shares" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (James Chirico, 50,904 shares): old title, new title

Inferred typo: the share class "Ordinary Share" is treated as the same class as "Ordinary Shares" on 2 holding lines, because the two spellings are nearly identical and each balance carried over exactly. Example (Robert Whitmore, 53,704 shares): old title, new title

Inferred typo: the share class "Oridnary Shares" is treated as the same class as "Ordinary Shares" on 3 holding lines, because the two spellings are nearly identical and each balance carried over exactly. Example (Malley O, 281,800 shares): old title, new title

Inferred typo: the share class "Ordinar Shares" is treated as the same class as "Ordinary Shares" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (Douglas Dehaan, 1,018 shares): old title, new title

Inferred typo: the share class "Ordinarty Shares" is treated as the same class as "Ordinary Shares" on 1 holding line, because the two spellings are nearly identical and each balance carried over exactly. Example (David Morton Jr., 34,945 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 methodology1,888 filings from SEC EDGAR, and how we read them

All 1,888 Forms 3, 4 and 5 filed for Seagate Technology (SEC CIK 1137789) from Dec 12, 2002 to Oct 2, 2026, retrieved from SEC EDGAR on Oct 9, 2026. Prices are the ones reported in each filing, often weighted averages. 3 filings were left out because Seagate Technology filed them as an owner of another company's stock. 3 older filings exist only on paper and could not be read.

Probable 3-for-1 stock split on or before Sep 16, 2005 (split date stated in a footnote). Splits aren't reported as transactions; 3 holding lines changed by exactly this ratio, so earlier share counts are restated.

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 (64)No filing in 18 months; last reported balances, not in any total
NameLast filedLast reported balance
Robert BruggeworthOct 22, 20246,591 shares, last reported balance as of Oct 19, 2024
Katherine SchuelkeDec 12, 202329,063 shares, last reported balance as of Dec 9, 2023
Edward ZanderOct 24, 202390,872 shares, last reported balance as of Oct 23, 2023
Ravi NaikMar 23, 202338,857 shares, last reported balance as of Mar 22, 2023
Jeffrey NygaardFeb 2, 2023102,154 shares, last reported balance as of Feb 1, 2023
Jeffrey FochtmanSep 14, 202214,736 shares, last reported balance as of Sep 12, 2022
Stephen LuczoMar 8, 20221,163,704,582 shares, last reported balance as of Mar 4, 2022
William Coleman IIIOct 23, 202014,936 shares, last reported balance as of Oct 21, 2020
James MurphyDec 23, 201910,569 shares, last reported balance as of Dec 20, 2019
Chong ParkOct 22, 201866,186 shares, last reported balance as of Oct 18, 2018
Mei ChengOct 22, 201820,047 shares, last reported balance as of Oct 18, 2018
Geraldine Hottier-FayonSep 25, 20188,217 shares, last reported balance as of Sep 22, 2018
Kathryn ScolnickSep 25, 20184,256 shares, last reported balance as of Sep 22, 2018
David Morton Jr.Jul 27, 201836,650 shares, last reported balance as of Jul 25, 2018
Philip BraceJan 16, 201816,069 shares, last reported balance as of Jan 11, 2018
Dambisa MoyoOct 25, 2017No balance on record
Frank BiondiOct 19, 201747,661 shares, last reported balance as of Oct 17, 2017
Kenneth MassaroniJun 14, 2017108,133 shares, last reported balance as of Jun 12, 2017
Mark ReMay 16, 201740,470 shares, last reported balance as of May 15, 2017
Regan MacPhersonNov 18, 201630,314 shares, last reported balance as of Nov 16, 2016
Kristen OnkenOct 20, 201623,729 shares, last reported balance as of Oct 18, 2016
Gregorio ReyesOct 23, 20151,787,555 shares, last reported balance as of Oct 21, 2015
Malley OSep 23, 20151,062,902 shares, last reported balance as of Sep 23, 2015
Douglas DehaanSep 23, 201532,517 shares, last reported balance as of Sep 23, 2015
Albert PimentelSep 23, 2015149,428 shares, last reported balance as of Sep 23, 2015
David RicharzApr 28, 2015103,752 shares, last reported balance as of Apr 24, 2015
James LernerMar 13, 201517,858 shares, last reported balance as of Mar 11, 2015
Lydia MarshallOct 23, 201443,785 shares, last reported balance as of Oct 21, 2014
Seh-Woong JeongOct 23, 20142,518 shares, last reported balance as of Oct 21, 2014
SAMSUNG ELECTRONICS CO LTD /FIOct 22, 201312,539,490 shares, last reported balance as of Oct 21, 2013
Robert WhitmoreMay 31, 2013235,084 shares, last reported balance as of May 30, 2013
John ThompsonAug 15, 2011293,820 shares, last reported balance as of Jan 24, 2011
David MarquardtDec 2, 2009302,911,447 shares, last reported balance as of Nov 30, 2009
David MarquardtDec 2, 20098,260,680 shares, last reported balance as of Dec 31, 2005
William BradleyOct 30, 200915,000 shares, last reported balance as of Oct 28, 2009
David AndersonOct 27, 20095,833 shares, last reported balance as of Oct 23, 2009
Terence CunninghamMar 10, 2009No balance on record
William WatkinsFeb 6, 20091,022,517,448 shares, last reported balance as of Jul 31, 2008
William WatkinsFeb 6, 200940,000 shares, last reported balance as of Nov 28, 2007
Donald KiernanNov 3, 200820,000 shares, last reported balance as of Oct 30, 2008
Charles PopeOct 29, 2008453,820 shares, last reported balance as of Oct 27, 2008
Brian DexheimerSep 16, 2008893,993 shares, last reported balance as of Sep 12, 2008
Glen PetersonSep 16, 200857,510 shares, last reported balance as of Sep 12, 2008
David WickershamSep 16, 2008656,671 shares, last reported balance as of Sep 12, 2008
Jerry GlembockiSep 16, 2008729,566 shares, last reported balance as of Sep 12, 2008
James DavidsonAug 11, 2008300,001,479 shares, last reported balance as of Aug 2, 2005
William HudsonAug 11, 20081,122,173 shares, last reported balance as of Jul 3, 2008
James DavidsonAug 11, 200867,333,737 shares, last reported balance as of Sep 25, 2007
Todd AbbottMay 20, 200818,500 shares, last reported balance as of May 9, 2008
Michael WingertSep 20, 20074,330 shares, last reported balance as of Feb 23, 2007
James ChiricoJul 26, 2007392,571 shares, last reported balance as of Jul 24, 2007
Mark KryderMay 3, 2007887,949 shares, last reported balance as of May 3, 2007
Karen RoggeNov 16, 20061,890 shares, last reported balance as of May 26, 2006
Glenn HutchinsAug 17, 2006300,001,479 shares, last reported balance as of Aug 2, 2005
Glenn HutchinsAug 17, 200655,086,412 shares, last reported balance as of Aug 16, 2006
Sac NewJan 4, 20061,572 shares, last reported balance as of Jan 3, 2006
James CoulterOct 31, 2005No balance on record
TPG SAC ADVISORS III CORPAug 4, 2005300,001,479 shares, last reported balance as of Aug 2, 2005
SILVER LAKE OFFSHORE AIV GP LTDAug 4, 2005347,718,087 shares, last reported balance as of Aug 2, 2005
Donald WaiteMar 8, 2004440,067 shares, last reported balance as of Jan 30, 2004
Jeremy TennenbaumFeb 9, 2004450,000 shares, last reported balance as of Feb 9, 2004
Townsend PorterDec 2, 20033,000 shares, last reported balance as of Nov 26, 2003
John WeyandtNov 6, 2003No balance on record
David BondermanNov 3, 2003No balance on record

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