Summit Midstream (SMC) appoints Carolyn Stone as new independent director

Rhea-AI Filing Summary

Summit Midstream Corporation reported that its board unanimously appointed Carolyn J. Stone as an independent Class II director, effective March 16, 2026. She will fill the board seat currently held by Marguerite Woung-Chapman, who will retire as of midnight on March 15, 2026. Ms. Woung-Chapman stated she has no disagreement with the company on its operations, practices, or policies, and there is no issue related to her retirement that needs to be brought to shareholders’ attention.

The company highlighted Ms. Stone’s extensive background in financial, accounting, and audit matters, as well as public-company governance and reporting. Her prior roles include serving as Senior Vice President, Chief Financial Officer, and Treasurer of Civeo Corporation, along with earlier executive and accounting leadership positions. She is a Certified Public Accountant and will receive compensation under Summit Midstream’s standard director compensation program.

8-K Event Classification

Item 5.02 — Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers

1 item

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers Governance

Key personnel changes including departures, elections, or appointments of directors and executive officers.

Understanding 8-K Material Events →

0002024218FALSE00020242182025-12-232025-12-23

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): December 23, 2025

Summit Midstream Corporation

(Exact name of registrant as specified in its charter)

Delaware

001-42201

99-3056990

(State or other jurisdiction

(Commission

(IRS Employer

of incorporation)

File Number)

Identification No.)

910 Louisiana Street, Suite 4200

Houston, TX 77002

(Address of principal executive office) (Zip Code)

(Registrants’ telephone number, including area code): (832) 413-4770

Not applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o			Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
o			Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
o			Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
o			Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Securities Act:

Title of each class			Trading Symbol(s)			Name of each exchange on which registered
Common Stock			SMC			New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.  o

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

Appointment of Director

On December 23, 2025, the board unanimously appointed Carolyn J. Stone as an independent director of the company to serve in Class II effective on March 16, 2026, in the seat being vacated by Marguerite Woung-Chapman, who notified the Board of her retirement effective as of midnight on March 15, 2026. Ms. Woung-Chapman has confirmed that she has no disagreement with the Company on any matter relating to its operations, practices, or policies, and there is no matter relating to her retirement that needs to be brought to the attention of the Company’s shareholders.

Ms. Stone, age 53, brings to the board financial, accounting, and audit expertise and extensive experience in public-company governance, reporting, and operations. Ms. Stone served as Senior Vice President, Chief Financial Officer, and Treasurer of Civeo Corporation, a NYSE-listed provider of hospitality services in the Australian natural resource regions and the Canadian oil sands, from November 2019 until March 2024. Prior to that, from 2014 to 2019, she served as Civeo’s VP, Controller and Corporate Secretary and as Chief Accounting Officer. Prior to joining Civeo, Ms. Stone served as CFO of Synagro Technologies Inc., a private equity-held environmental services company. Prior to Synagro, Ms. Stone served eleven years in multiple roles at Dynegy Inc., including Chief Accounting Officer, Treasurer, and Controller. She started her career at PriceWaterhouseCoopers LLP, where she worked in the firm’s audit practice. She is a Certified Public Accountant and earned both her Bachelor of Business Administration and Master in Professional Accounting degrees from The University of Texas at Austin.

There are no arrangements or understandings between Ms. Stone and any other person pursuant to which she was selected as a director. Ms. Stone will receive compensation under the Company’s director compensation program.

Exhibit Number						Description
104						Cover Page Interactive Data File – the cover page XBRL tags are embedded within the Inline XBRL document

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

						Summit Midstream Corporation
						(Registrant)
Dated:			December 29, 2025			/s/ James Johnston
						James Johnston, Executive Vice President, General Counsel and Chief Compliance Officer

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FAQ

What board change did Summit Midstream Corporation (SMC) disclose?

Summit Midstream Corporation disclosed that its board unanimously appointed Carolyn J. Stone as an independent Class II director, effective March 16, 2026, to succeed Marguerite Woung-Chapman, who will retire as of midnight on March 15, 2026.

Why is director Marguerite Woung-Chapman leaving Summit Midstream (SMC)?

Marguerite Woung-Chapman notified the board of her retirement effective as of midnight on March 15, 2026. She confirmed she has no disagreement with the company on any matter relating to its operations, practices, or policies, and there is no matter related to her retirement that must be brought to shareholders’ attention.

Who is Carolyn J. Stone, the new independent director at Summit Midstream (SMC)?

Carolyn J. Stone, age 53, brings financial, accounting, and audit expertise and extensive public-company governance and reporting experience. She previously served as Senior Vice President, Chief Financial Officer, and Treasurer of Civeo Corporation, and earlier held senior finance and accounting roles at Civeo, Synagro Technologies Inc., and Dynegy Inc., after starting her career at PriceWaterhouseCoopers LLP.

Does Carolyn J. Stone have any special arrangements related to her appointment to the SMC board?

The company stated there are no arrangements or understandings between Carolyn J. Stone and any other person pursuant to which she was selected as a director. She will receive compensation under Summit Midstream’s standard director compensation program.

What qualifications does the new Summit Midstream (SMC) director bring?

Carolyn J. Stone brings financial, accounting, and audit expertise and experience with public-company governance, reporting, and operations. She is a Certified Public Accountant and holds a Bachelor of Business Administration and a Master in Professional Accounting from The University of Texas at Austin.

Is there any shareholder issue or conflict tied to the director retirement at SMC?

The company reported that Marguerite Woung-Chapman has no disagreement with Summit Midstream regarding its operations, practices, or policies, and there is no matter related to her retirement that needs to be brought to shareholders’ attention.