Seagate insider plans 18,200-share tax-cover sale

Rhea-AI Filing Summary

Seagate Technology Holdings plc (STX) insider William D. Mosley has filed a notice under Rule 144 to sell up to 18,200 shares of common stock through Morgan Stanley, with an indicated aggregate market value of 15,458,257.36, based on a planned sale date of 08/21/2026 on NASDAQGS. The notice lists Seagate common shares outstanding of 226,644,518. Mosley acquired shares via restricted stock unit vesting on 08/20/2026, and the notice states that any sales are to be made pursuant to an issuer-mandated sell-to-cover arrangement solely to satisfy tax withholding obligations.

Key Figures

Planned shares to be sold: 18,200 shares Aggregate market value of planned sale: 15,458,257.36 Shares outstanding: 226,644,518 shares +5 more

8 metrics

Planned shares to be sold 18,200 shares Common stock under Rule 144 through Morgan Stanley

Aggregate market value of planned sale 15,458,257.36 For 18,200 Seagate common shares

Shares outstanding 226,644,518 shares Seagate common stock outstanding referenced in the notice

RSU vesting 1 6,404 shares Common stock from restricted stock unit vesting on 08/20/2026

RSU vesting 2 6,320 shares Common stock from restricted stock unit vesting on 08/20/2026

RSU vesting 3 21,065 shares Common stock from restricted stock unit vesting on 08/20/2026

Sale on 08/03/2026 30,000 shares; 24,511,131.27 Common stock with aggregate market value reported for that date

Sale on 07/01/2026 30,000 shares; 27,444,658.12 Common stock with aggregate market value reported for that date

Key Terms

Rule 144, Restricted Stock Unit Vesting, sell-to-cover, aggregate market value

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Unit Vesting financial

"Common stock | 08/20/2026 | Restricted Stock Unit Vesting | Issuer"

sell-to-cover financial

"Sales to be made pursuant to Issuer mandated sell-to-cover solely"

Sell-to-cover is when part of newly issued or exercised company stock is immediately sold to pay required taxes and fees, so the recipient keeps the remaining shares. For investors this matters because it reduces the number of shares insiders or employees actually hold after a grant, can create small, routine share sales that aren’t signal of cashing out, and slightly increases share supply on the market—like selling a portion of a paycheck to cover the tax bill.

aggregate market value financial

"Common Stock | Morgan Stanley ... | 18200 | 15458257.36"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

What does Seagate Technology (STX) disclose in this Form 144 for William D. Mosley?

The filing states that William D. Mosley may sell up to 18,200 Seagate common shares under Rule 144 through Morgan Stanley, tied to a planned sale date of 08/21/2026, with an indicated aggregate market value of 15,458,257.36.

How many Seagate (STX) shares are planned for sale and on what exchange?

The notice covers a potential sale of 18,200 shares of Seagate common stock, to be sold on NASDAQGS. The aggregate market value shown for these shares is 15,458,257.36 as part of the Rule 144 disclosure.

What reason is given for William D. Mosley’s potential Seagate (STX) share sales?

The remarks state that any sales are to be made pursuant to an issuer mandated sell-to-cover arrangement, used solely to satisfy tax withholding obligations arising from equity compensation, with a power of attorney attached.

What recent Seagate (STX) equity awards to William D. Mosley are listed?

The filing lists restricted stock unit vestings on 08/20/2026 for 6,404, 6,320, and 21,065 Seagate common shares, each described as compensation for services from the issuer.

What Seagate (STX) share sales by William D. Mosley occurred in the prior three months?

The notice reports common stock sales including 30,000 shares on 08/03/2026 with aggregate market value 24,511,131.27, 30,000 shares on 07/01/2026 at 27,444,658.12, and additional smaller transactions in June 2026.

How many Seagate (STX) shares are reported outstanding in this Form 144?

The Rule 144 information states that Seagate common shares outstanding are 226,644,518, presented in connection with the planned sale of 18,200 shares of common stock.

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Available on EDGAR 08/21/2026 - 07:34 PM Accepted by SEC EDGAR 08/21/2026 - 07:34 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001388390
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	Seagate Technology Holdings plc
SEC File Number	001-31560
Address of Issuer	121 WOODLANDS AVENUE 5 SINGAPORE SINGAPORE 739009
Phone	65 6412 5172
Name of Person for Whose Account the Securities are To Be Sold	MOSLEY WILLIAM D
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer
Relationship to Issuer	Director

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common Stock	Morgan Stanley 1 New York Plaza 8th Floor New York NY 10004	18200	15458257.36	226644518	08/21/2026	NASDAQGS

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common stock	08/20/2026	Restricted Stock Unit Vesting	Issuer			6404	08/20/2026	Compensation for services
Common Stock	08/20/2026	Restricted Stock Unit Vesting	Issuer			6320	08/20/2026	Compensation for services
Common Stock	08/20/2026	Restricted Stock Unit Vesting	Issuer			21065	08/20/2026	Compensation for services

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
William D. Mosley 47488 Kato Rd Fremont CA 94538	Common Stock	08/03/2026	30000	24511131.27
William D. Mosley 47488 Kato Road Fremont CA 94538	Common Stock	07/01/2026	30000	27444658.12
William D. Mosley 474888 Kato Road Fremont CA 94538	Common Stock	06/12/2026	1768	1556394.00
William D. Mosley 47488 Kato Road Fremont CA 94538	Common Stock	06/09/2026	2855	2345874.00
William D. Mosley 47488 Kato Road Fremont CA 94538	Common Stock	06/01/2026	30000	27347824.00

144: Remarks and Signature

Remarks	Sales to be made pursuant to Issuer mandated sell-to-cover solely to satisfy tax withholding obligations. PoA attached.
Date of Notice	08/21/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	08/20/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Dawn Ledbetter. Attorney-in-Fact for William D. Mosley
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)