[SCHEDULE 13D/A] Summit Midstream Corporation SEC Filing

Rhea-AI Filing Summary

Connect Midstream, LLC and affiliated Tailwater entities report beneficial ownership of 6,644,627 shares of Summit Midstream Corp common stock, representing 35.4% of the diluted class. That total includes 6,524,467 Common Units convertible into the same number of common shares and Class B shares that convey voting rights but no economic interest, plus 120,160 directly held common shares. Conversion of Common Units forfeits corresponding Class B shares for no consideration.

The amendment discloses that recent open-market purchases of 72,759 shares on 8/26/2025 at an average $20.46 and 47,401 shares on 8/27/2025 at an average $20.50 were financed with working capital. Ownership is held through a chain of entities culminating in Tailwater Capital LLC, with Jason H. Downie and Edward Herring identified as managing partners.

Positive

• Material ownership disclosed: 6,644,627 shares beneficially owned representing 35.4% of diluted common stock
• Recent purchases documented with dates and prices: 72,759 shares at avg $20.46 on 8/26/2025 and 47,401 shares at avg $20.50 on 8/27/2025
• Financing clarity: Purchases were financed with working capital, explicitly disclosed

Negative

• None.

Insights

Securities Analyst

TL;DR Ownership stake of 35.4% via convertible units and direct shares is material and changes governance and voting dynamics.

The filing discloses a significant passive-to-active ownership position: 6,644,627 shares equivalent equal to 35.4% of diluted common stock. The structure mixes economically convertible Common Units with Class B voting shares that carry voting power until conversion, which preserves voting influence while delaying economic dilution. Recent open-market purchases totaling 120,160 shares over two days at roughly $20.46–$20.50 further solidify the position. Financing with working capital indicates no third-party financing disclosed. For investors, this alters potential control and voting outcome scenarios; the exact governance effects depend on future conversions or additional purchases.

Corporate Governance Expert

TL;DR The combination of convertible units and Class B shares concentrates voting power and may affect board influence and shareholder decision-making.

The reporting persons hold convertible economic interests paired with separate Class B voting shares that grant voting rights without economic exposure until conversion. This dual-holding preserves voting control while allowing staged economic exposure on conversion. The ownership chain shows clear common control from Tailwater entities to Connect Midstream, creating a unified voting bloc. The filing does not state any agreements to change board composition or launch transactions, but the disclosed stake is large enough to be material to governance outcomes.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 1)

Summit Midstream Corp

(Name of Issuer)

Common Stock, par value $0.01 per share

(Title of Class of Securities)

86614G101

(CUSIP Number)

Brian Blakeman
c/o Connect Midstream, LLC, 2021 McKinney Ave, Suite 1250
Dallas, TX, 75201
(214) 269-8753

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

08/26/2025

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

SCHEDULE 13D

CUSIP No. 86614G101

1

Name of reporting person

Connect Midstream, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,644,627.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,644,627.00

11

Aggregate amount beneficially owned by each reporting person

6,644,627.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

35.4 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) Row 11 represents (i) 6,524,467 shares of common stock of the Issuer ("Common Stock") issuable in respect of an equivalent number of common units ("Common Units") of the Partnership (as defined below) and class B common stock of the Issuer ("Class B Shares") beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock beneficially owned by the Reporting Persons. (2) Row 13 is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons.

SCHEDULE 13D

CUSIP No. 86614G101

1

Name of reporting person

Tailwater Energy Fund III LP

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,644,627.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,644,627.00

11

Aggregate amount beneficially owned by each reporting person

6,644,627.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

35.4 %

14

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person:

(1) Row 11 represents (i) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units of the Partnership (as defined below) and Class B Shares beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock beneficially owned by the Reporting Persons. (2) Row 13 is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons.

SCHEDULE 13D

CUSIP No. 86614G101

1

Name of reporting person

Tailwater Capital LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,644,627.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,644,627.00

11

Aggregate amount beneficially owned by each reporting person

6,644,627.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

35.4 %

14

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person:

(1) Row 11 represents (i) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units of the Partnership (as defined below) and Class B Shares beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock beneficially owned by the Reporting Persons. (2) Row 13 is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons.

SCHEDULE 13D

CUSIP No. 86614G101

1

Name of reporting person

Jason H. Downie

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,644,627.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,644,627.00

11

Aggregate amount beneficially owned by each reporting person

6,644,627.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

35.4 %

14

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person:

(1) Row 11 represents (i) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units of the Partnership (as defined below) and Class B Shares beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock beneficially owned by the Reporting Persons. (2) Row 13 is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons.

SCHEDULE 13D

CUSIP No. 86614G101

1

Name of reporting person

Edward Herring

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

OO

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 6,644,627.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 6,644,627.00

11

Aggregate amount beneficially owned by each reporting person

6,644,627.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

35.4 %

14

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person:

(1) Row 11 represents (i) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units of the Partnership (as defined below) and Class B Shares beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock beneficially owned by the Reporting Persons. (2) Row 13 is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons.

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common Stock, par value $0.01 per share
(b)	Name of Issuer: Summit Midstream Corp
(c)	Address of Issuer's Principal Executive Offices: 901 Louisiana Street, Suite 4200, Houston, TEXAS , 77002.
Item 1 Comment: This Amendment No. 1 to Schedule 13D ("Amendment No. 1") amends the Statement on Schedule 13D (as amended, the "Schedule 13D") initially filed on December 3, 2024 with the Securities and Exchange Commission and relates to the Common Stock of Summit Midstream Corporation (the "Issuer").
Item 3.	Source and Amount of Funds or Other Consideration
	Item 3 of the Schedule 13D is hereby amended to include the following at the end thereof: The purchases disclosed in Item 5(c) of this Amendment No. 1 were financed with working capital.
Item 5.	Interest in Securities of the Issuer
(a)	The information set forth in rows eleven and thirteen on the cover pages of this Amendment No. 1 is incorporated by reference into this Item 5(a). The reported securities represent (i) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons and (ii) 120,160 shares of Common Stock directly held by Connect Midstream, which represents 35.4% of the shares of Common Stock outstanding as of the date hereof. Such percentage is calculated assuming 18,766,331 shares of Common Stock outstanding based upon (i) 12,241,864 Common Stock outstanding as of July 31, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the SEC on August 11, 2025, as increased by (ii) 6,524,467 shares of Common Stock issuable in respect of an equivalent number of Common Units and Class B Shares beneficially owned by the Reporting Persons. In this regard, Connect Midstream is the direct holder of (i) 6,524,467 Common Units which are convertible into an equivalent number of shares of Common Stock and the direct holder of (ii) 120,160 shares of Common Stock. Connect Midstream is also the direct holder of 6,524,467 Class B Shares, which do not represent an economic interest in the Issuer but provide holders of Common Units with voting rights. Upon conversion of Common Units into shares of Common Stock, an equivalent number of Class B Shares are forfeited for no consideration. Tailwater Energy is the sole member of Connect Midstream. TW GP EF-III LP is the general partner of Tailwater Energy. TW GP EF-III GP, LLC is the general partner of TW GP EF-III LP. Tailwater Capital LLC is the sole member of TW GP EF-III GP, LLC. Jason H. Downie and Edward Herring are both Managing Partners of Tailwater Capital. As a result of these relationships, each of the foregoing may be deemed to beneficially own the reported securities, provided that neither the filing of this Schedule 13D nor any of its contents shall be deemed to constitute an admission by any of the Reporting Persons or any of the foregoing that it is the beneficial owner of any of the Common Stock referred to herein for the purposes of Section 13(d) of the Act, or for any other purpose.
(b)	The information set forth in rows seven through ten on the cover pages of this Amendment No. 1 and the information set forth in Item 5(a) of this Amendment No. 1 are each incorporated by reference into this Item 5(b).
(c)	Connect Midstream purchased shares of Common Stock on the public market within the prior 60 days as follows: Date Purchase/(Sale) Amount of Shares Average Price Low Price High Price 8/26/25 Purchase 72,759 $20.46 $19.87 $20.87 8/27/25 Purchase 47,401 $20.50 $20.35 $20.82 The Reporting Persons undertake to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, full information regarding the number of shares purchased or sold at each separate price within the ranges set forth above. Except for the foregoing or as otherwise set forth herein, each of the Reporting Persons reports that neither it, nor to its knowledge, any other person named in Item 2 of the Schedule 13D, has effected any transactions in Common Stock during the past 60 days.

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.

Connect Midstream, LLC

Signature:	/s/ Jason H. Downie
Name/Title:	Jason H. Downie/Director
Date:	08/28/2025

Tailwater Energy Fund III LP

Signature:	/s/ Jason H. Downie
Name/Title:	Jason H. Downie/Managing Partner
Date:	08/28/2025

Tailwater Capital LLC

Signature:	/s/ Jason H. Downie
Name/Title:	Jason H. Downie/Managing Partner
Date:	08/28/2025

Jason H. Downie

Signature:	/s/ Jason H. Downie
Name/Title:	Jason H. Downie
Date:	08/28/2025

Edward Herring

Signature:	/s/ Edward Herring
Name/Title:	Edward Herring
Date:	08/28/2025

Comments accompanying signature:

Tailwater Energy Fund III LP is the sole member of Connect Midstream, LLC. TW GP EF-III LP is the general partner of Tailwater Energy Fund III LP. TW GP EF-III GP, LLC is the general partner of TW GP EF-III LP. Tailwater Capital LLC is the sole member of TW GP EF-III GP, LLC. Jason H. Downie and Edward Herring are each a Managing Partner of Tailwater Capital LLC.

FAQ

What stake does Tailwater/Connect Midstream report in Summit Midstream (SMC)?

The reporting persons disclose beneficial ownership of 6,644,627 shares, equal to 35.4% of diluted common stock.

How is the 6,644,627 figure composed?

It includes 6,524,467 Common Units convertible into common shares and Class B shares with voting rights, plus 120,160 directly held common shares.

Did the reporting persons buy shares recently and at what prices?

Yes. They purchased 72,759 shares on 8/26/2025 at an average $20.46 and 47,401 shares on 8/27/2025 at an average $20.50.

How were the recent purchases financed?

The amendment states the purchases disclosed were financed with working capital.

Who controls the reporting entities and who signed the filing?

Tailwater Energy Fund III LP is sole member of Connect Midstream; signatures include Jason H. Downie and Edward Herring dated 08/28/2025.