D1 Capital reports 4.6% stake in Flowserve

Flowserve Corporation ownership disclosure: D1 Capital Partners L.P. and Daniel Sundheim report beneficial ownership of 5,874,441 shares of Flowserve common stock, representing 4.6% of the class based on 127,260,329 shares outstanding as of February 12, 2026.

Rhea-AI Filing Summary

Flowserve Corporation ownership disclosure: D1 Capital Partners L.P. and Daniel Sundheim report beneficial ownership of 5,874,441 shares of Flowserve common stock, representing 4.6% of the class based on 127,260,329 shares outstanding as of February 12, 2026. The shares are reported as held by the Investment Vehicle and/or its subsidiary with shared voting and dispositive power.

The filing is a Schedule 13G/A amendment signed on 05/15/2026 by the reporting persons; it states the Investment Manager may be deemed to beneficially own the shares held by the Investment Vehicle and that Mr. Sundheim indirectly controls the Investment Manager.

Insights

Institutional Ownership Analyst

Large passive stake disclosure: 4.6% reported by D1 Capital.

The filing shows D1 Capital Partners L.P. and Daniel Sundheim reporting beneficial ownership of 5,874,441 shares with shared voting and dispositive powers. The ownership percentage is calculated using 127,260,329 shares outstanding as of February 12, 2026.

Because this is a Schedule 13G/A amendment, it reflects an ownership disclosure rather than a transaction. Subsequent filings would show any change; timing and transactions are not detailed here.

Compliance & Governance Specialist

Filing attributes ownership to an investment manager and an individual controller.

The statement clarifies the Investment Manager is the entity reporting the position held by the Investment Vehicle and that Mr. Sundheim indirectly controls the manager. It includes the Investment Vehicle's right to receive dividends and proceeds from sales.

Signatures show amendment execution on 05/15/2026. Any questions about control or voting should be resolved by reviewing future or related Section 13 filings.

Key Figures

Reported shares beneficially owned: 5,874,441 shares Percent of class: 4.6% Shares outstanding (used): 127,260,329 shares +2 more

5 metrics

Reported shares beneficially owned 5,874,441 shares Shared voting/dispositive power reported by D1 Capital

Percent of class 4.6% Calculated using outstanding shares as of <date>February 12, 2026</date>

Shares outstanding (used) 127,260,329 shares As of <date>February 12, 2026</date>, cited from Form 10-K

CUSIP 34354P105 Flowserve common stock identifier

Amendment signature date 05/15/2026 Schedule 13G/A signed by reporting persons

Key Terms

Schedule 13G/A, shared dispositive power, beneficial ownership

3 terms

Schedule 13G/A regulatory

"Amendment No. 1 and schedule title indicating a beneficial ownership amendment"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

shared dispositive power regulatory

"Shared Dispositive Power 5,874,441.00 shown on the cover page"

beneficial ownership regulatory

"may be deemed to beneficially own the shares of common stock held by the Investment Vehicle"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does D1 Capital report in Flowserve (FLS)?

D1 Capital reports beneficial ownership of 5,874,441 shares, equal to 4.6% of Flowserve's common stock based on 127,260,329 shares outstanding as of February 12, 2026.

Who is reported as the beneficial owner in the Schedule 13G/A for FLS?

The filing names D1 Capital Partners L.P. as the Investment Manager and Daniel Sundheim as the related individual who indirectly controls the manager and may be deemed to beneficially own the shares.

What voting or dispositive power is disclosed by D1 Capital in the filing?

The Schedule 13G/A shows shared voting power and shared dispositive power over 5,874,441 shares; sole voting and sole dispositive powers are reported as 0 for the reporting persons.

What outstanding share count was used to calculate the 4.6% figure?

The percentage is calculated using 127,260,329 shares outstanding as of February 12, 2026, cited from the company's Annual Report on Form 10-K for the year ended December 31, 2025.

Does the filing state who receives dividends or sale proceeds?

Yes. The filing states the Investment Vehicle (and/or its subsidiary) has the right to receive dividends and the power to direct receipt of proceeds from sales of the reported shares.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/15/2026 - 12:04 PM EDT Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Flowserve Corporation

(Name of Issuer)

Common Stock, par value $1.25 per share

(Title of Class of Securities)

34354P105

(CUSIP Number)

03/31/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 34354P105

1

Names of Reporting Persons

D1 Capital Partners L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,874,441.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,874,441.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,874,441.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.6 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): 34354P105

1

Names of Reporting Persons

Daniel Sundheim

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,874,441.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,874,441.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,874,441.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.6 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Flowserve Corporation
(b)	Address of issuer's principal executive offices: 5215 N. O'Connor Blvd., Suite 700, Irving, Texas 75039
Item 2.
(a)	Name of person filing: This statement is filed by D1 Capital Partners L.P. (the "Investment Manager") and Daniel Sundheim (the "Mr. Sundheim"). The foregoing persons are hereinafter sometimes referred to as the "Reporting Persons." The Investment Manager is a registered investment adviser and serves as the investment manager of private investment vehicles and accounts, including D1 Capital Partners Master LP (the "Investment Vehicle"), and may be deemed to beneficially own the shares of common stock, par value $1.25 per share (the "Common Stock") of Flowserve Corporation (the "Company") held by the Investment Vehicle and/or its subsidiary. Mr. Sundheim indirectly controls the Investment Manager and may be deemed to beneficially own the shares of Common Stock issuable held by the Investment Vehicle and/or its subsidiary. The filing of this statement should not be construed as an admission that any Reporting Person is, for the purposes of Section 13 of the Securities Exchange Act of 1934, as amended, the beneficial owner of the securities reported herein.
(b)	Address or principal business office or, if none, residence: D1 Capital Partners L.P. 9 West 57th Street, 36th Floor New York, New York 10019 Daniel Sundheim c/o D1 Capital Partners L.P. 9 West 57th Street, 36th Floor New York, New York 10019
(c)	Citizenship: Investment Manager - Delaware Mr. Sundheim - United States of America
(d)	Title of class of securities: Common Stock, par value $1.25 per share
(e)	CUSIP No.: 34354P105
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 127,260,329 shares of Common Stock outstanding as of February 12, 2026, as reported in the Company's Annual Report on Form 10-K for the year ended December 31, 2025, filed with the Securities and Exchange Commission on February 17, 2026.
(b)	Percent of class: 4.6%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(ii) Shared power to vote or to direct the vote: The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(iii) Sole power to dispose or to direct the disposition of: The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
	(iv) Shared power to dispose or to direct the disposition of: The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. See Item 2(a). The Investment Vehicle (and/or its subsidiary) has the right to receive and the power to direct the receipt of dividends from, and the proceeds from the sale of, the shares of Common Stock reported herein.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

D1 Capital Partners L.P.

Signature:	/s/ Amanda Hector
Name/Title:	Amanda Hector, General Counsel and Chief Compliance Officer
Date:	05/15/2026

Daniel Sundheim

Signature:	/s/ Daniel Sundheim
Name/Title:	Daniel Sundheim, Individually
Date:	05/15/2026