MOSLEY WILLIAM D

CIK: 0001388390
Primary company: Seagate Technology Holdings plc (STX)

MOSLEY WILLIAM D is a corporate insider at Seagate Technology Holdings plc (STX) filing SEC Form 4 transactions. 597 transactions across 2 companies, totaling $0 in purchases and $191,039,387 in sales. Source: SEC EDGAR.

AI Insider Summary

William D. Mosley (CIK 0001388390, 510 transactions) has a uniquely one-sided Form 4 record at Seagate Technology Holdings plc (STX): every single buy-side event in the lifetime aggregate is zero, while the sell side totals 3,754,548 shares across 505 transactions since 2007. The most recent session on May 20, 2026 is a textbook example of how that aggregate was built — 18 consecutive market sells in one day, ranging from 80 shares at $880.19 down to 120 shares at $742.01, a single disposition order algorithmically sliced and executed across a 15-point price arc as the stock drifted lower within the session. The only non-sell event in the recent 25-transaction window is a paired option exercise on June 11, 2026: 3,319 shares exercised at $46.23 (deep in-the-money given the then-market near $750), with no corresponding sale reported in the same filing — meaning Mosley is still holding the exercised shares. Against a lifetime sell total of 3.75M shares, the one in-the-money exercise that did not immediately get sold is a small island of retention in an otherwise pure distribution profile.

Mosley's lifetime STX record is 3,754,548 sell-side shares and zero buy-side shares — not a low buy count, not a mostly-sell record, but literally no open-market buy (code P) in over 500 transactions spanning 2007 to present. That is unusual even for a long-tenured executive whose equity compensation has funded ordinary portfolio diversification; most executives with that many transactions accumulate at least a small pattern of dividend-reinvestment or opportunistic buys alongside their disposition activity.

The May 20, 2026 session as a microcosm.

Analysis generated by 13F Insight from SEC Form 4 filing data. Methodology
Total Transactions
597
Total Buy Value
$0
Total Sell Value
$191.04M
Net Activity
$-191.04M
Last Transaction
Sep 2026
Companies
2

Companies

Transaction History

Source: SEC EDGAR Form 4 insider transaction filings.

Seagate Technology Holdings plc
STX
Type
Sale
Shares
1,315
Price
$862.14
Value
$1.13M
Seagate Technology Holdings plc
STX
Type
Sale
Shares
1,533
Price
$862.13
Value
$1.32M
Seagate Technology Holdings plc
STX
Type
Exercise
Shares
2,415
Price
-
Value
-
Seagate Technology Holdings plc
STX
Type
Exercise
Shares
2,815
Price
-
Value
-
Seagate Technology Holdings plc
STX
Type
Exercise
Shares
2,415
Price
-
Value
-
Seagate Technology Holdings plc
STX
Type
Exercise
Shares
2,815
Price
-
Value
-
Seagate Technology Holdings plc
STX
Type
Exercise
Shares
14,000
Price
$46.23
Value
$647K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
80
Price
$832.04
Value
$67K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
80
Price
$830.36
Value
$66K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
80
Price
$829.10
Value
$66K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
120
Price
$827.90
Value
$99K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
340
Price
$826.86
Value
$281K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
580
Price
$826.00
Value
$479K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
600
Price
$824.93
Value
$495K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
1,240
Price
$824.05
Value
$1.02M
Seagate Technology Holdings plc
STX
Type
Sale
Shares
600
Price
$822.89
Value
$494K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
480
Price
$822.05
Value
$395K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
920
Price
$820.89
Value
$755K
Seagate Technology Holdings plc
STX
Type
Sale
Shares
1,320
Price
$819.84
Value
$1.08M
Seagate Technology Holdings plc
STX
Type
Sale
Shares
1,040
Price
$818.78
Value
$852K