This is the public record of open-market stock transactions William D. Mosley has reported to the SEC on Form 4 as CEO of Seagate Technology Holdings plc (STX). Every figure below is the reported share count multiplied by the reported price, so the dollar amounts are exact disclosed values rather than estimates. It is a record of what has been filed, not a portfolio or a recommendation, and insider selling in particular is routine and rarely a signal on its own.
Most of William D. Mosley's sales were pre-scheduled or tax-related rather than discretionary, which further weakens any read of them as a market call.
All 20 disclosed transactions, newest filing first.
How many shares has William D. Mosley bought and sold?
William D. Mosley has disclosed 20 Form 4 transactions in the record we track, from Aug 1, 2025 to Aug 21, 2026: 20 sales worth $183,686,475 and no open-market purchases. Each figure is the reported share count multiplied by the reported price, so these are exact disclosed amounts, not estimates.
Is William D. Mosley selling a bearish signal?
Not on its own. Insiders sell for many reasons that have nothing to do with a view on the stock — diversification, taxes, estate planning, or a pre-scheduled plan set up months earlier. Of the 20 sales on this record, 16 were made under a Rule 10b5-1 plan and 0 were automatic tax withholding on vesting shares, leaving 4 that were the insider's own discretionary decision (worth $29,308,323). Buying is the cleaner signal, because there is only one reason to buy. This page is a record, not a recommendation.
What is William D. Mosley's role?
William D. Mosley files as CEO of Seagate Technology Holdings plc (STX). That role is taken from the Form 4 filings themselves. A Form 4 is filed with the SEC within two business days of an insider buying or selling their own company's stock.
What was William D. Mosley's largest single transaction?
The largest single transaction on record is a sell of 30,000 shares of STX at $751.29, worth $22,538,569, filed May 21, 2026.
How current is this record?
The most recent Form 4 here was filed Aug 24, 2026. Insiders have two business days to file after a trade, so this is close to real time, but it is a record of what has been disclosed, not a statement of what William D. Mosley currently holds. Amounts are open-market and plan transactions reported on Form 4; grants and option exercises are not counted as buys.
Source: Form 4 filings submitted to the SEC, the same public documents behind our insider trading tracker. Figures are open-market and plan transactions only; grants and option exercises are not counted as buys. A disclosure is not evidence of a market view, and none of this is investment advice. See the full STX stock page for price, filings and coverage.