Yorktown Energy Partners X and affiliates report their beneficial ownership in Solaris Energy Infrastructure, Inc. Class A common stock in an amended Schedule 13G filing. The reporting group holds 5,079,234 Solaris LLC Units and corresponding Class B common shares, which are exchangeable into the same number of Class A shares on a one-for-one basis under the Solaris LLC agreement.
Based on 65,831,540 Class A shares outstanding as of August 3, 2026, plus 5,079,234 Class A shares issuable upon exchange, the filing reports an approximate 7.2% beneficial ownership position. Voting and dispositive power over these securities is shared among Yorktown Energy Partners X, L.P., Yorktown X Company LP, and Yorktown X Associates LLC, with certain beneficial ownership expressly disclaimed beyond their pecuniary interests.
Beneficially owned exchangeable securities5,079,234 units/sharesClass B common stock and Solaris LLC Units exchangeable into Class A shares
Beneficial ownership percentage7.2%Reported stake in Class A common stock on an as-exchanged basis
Class A shares outstanding65,831,540 sharesClass A common stock outstanding as of August 3, 2026
Key Terms
Schedule 13G, beneficial ownership, Solaris LLC Units, disclaim beneficial ownership, +1 more
5 terms
Schedule 13Gregulatory
"Beneficial ownership of the Class A common stock is being reported hereunder solely because"
A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.
beneficial ownershipregulatory
"Neither the filing of this nor any of its contents shall be deemed to constitute an admission by any reporting person that it is the beneficial owner"
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.
Solaris LLC Unitsfinancial
"5,079,234 membership interests ("Solaris LLC Units") in Solaris Energy Infrastructure, LLC"
disclaim beneficial ownershipregulatory
"Yorktown X Company and Yorktown X Associates disclaim beneficial ownership of the securities owned by Yorktown X"
shared voting powerfinancial
"Shared Voting Power 5,079,234.00"
Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.
FAQ
What ownership stake in Solaris Energy Infrastructure (SEI) does Yorktown report in this Schedule 13G/A?
Yorktown and its affiliates report beneficial ownership of 5,079,234 Solaris LLC Units and Class B shares, exchangeable one-for-one into Class A shares, representing about 7.2% of Solaris Energy Infrastructure’s Class A common stock on an as-exchanged basis.
How many Solaris Energy Infrastructure (SEI) shares are outstanding for calculating Yorktown’s 7.2% stake?
The reported 7.2% beneficial ownership is based on 65,831,540 Class A common shares outstanding as of August 3, 2026, plus 5,079,234 Class A shares issuable upon exchange of Class B shares and Solaris LLC Units held by Yorktown.
Which Yorktown entities are reporting ownership of Solaris Energy Infrastructure (SEI)?
The reporting group comprises Yorktown Energy Partners X, L.P., Yorktown X Company LP (its general partner), and Yorktown X Associates LLC (general partner of Yorktown X Company). All are Delaware entities sharing voting and dispositive power over the reported securities.
What type of securities does Yorktown hold related to Solaris Energy Infrastructure (SEI)?
Yorktown directly holds 5,079,234 shares of Class B common stock and 5,079,234 Solaris LLC Units. These are exchangeable for an equal number of Class A common shares pursuant to the Second Amended and Restated Limited Liability Company Agreement of Solaris LLC.
Does Yorktown fully acknowledge beneficial ownership of all Solaris Energy Infrastructure (SEI) securities reported?
No. The filing states that neither the submission nor its contents constitutes an admission of beneficial ownership for Section 13(d) or other purposes, and Yorktown X Company and Yorktown X Associates disclaim beneficial ownership beyond their pecuniary interests.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 4)
Solaris Energy Infrastructure, Inc.
(Name of Issuer)
Class A common stock, par value $0.01 per share
(Title of Class of Securities)
83418M103
(CUSIP Number)
05/06/2026
(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):
83418M103
1
Names of Reporting Persons
YORKTOWN ENERGY PARTNERS X, 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
5,079,234.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
5,079,234.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,079,234.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
83418M103
1
Names of Reporting Persons
YORKTOWN X COMPANY LP
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
5,079,234.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
5,079,234.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,079,234.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
PN
SCHEDULE 13G
CUSIP Number(s):
83418M103
1
Names of Reporting Persons
YORKTOWN X ASSOCIATES LLC
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
5,079,234.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
5,079,234.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
5,079,234.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
OO
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Solaris Energy Infrastructure, Inc.
(b)
Address of issuer's principal executive offices:
9651 Katy Freeway, Suite 300, Houston, Texas 77024.
Item 2.
(a)
Name of person filing:
This statement is jointly filed by Yorktown Energy Partners X, L.P., a Delaware limited partnership ("Yorktown X"), Yorktown X Company LP, a Delaware limited partnership and the general partner of Yorktown X ("Yorktown X Company"), and Yorktown X Associates LLC, a Delaware limited liability company and the general partner of Yorktown X Company ("Yorktown X Associates", and collectively, with Yorktown X and Yorktown X Company, the "Reporting Persons").
(b)
Address or principal business office or, if none, residence:
The principal business office address of Yorktown X, Yorktown X Company and Yorktown X Associates is 410 Park Avenue, 20th Floor, New York, New York 10022.
(c)
Citizenship:
Each of Yorktown X, Yorktown X Company and Yorktown X Associates is organized under the laws of the state of Delaware.
(d)
Title of class of securities:
Class A common stock, par value $0.01 per share
(e)
CUSIP No.:
83418M103
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 pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
Beneficial ownership of the Class A common stock, par value $0.01 per share ("Class A Common Stock"), of the Issuer referred to herein is being reported hereunder solely because the reporting person directly owns 5,079,234 shares of Class B common stock of the Issuer ("Class B Common Stock") and 5,079,234 membership interests ("Solaris LLC Units") in Solaris Energy Infrastructure, LLC ("Solaris LLC"), which are exchangeable for shares of Class A Common Stock on a one-for-one basis, pursuant to the Second Amended and Restated Limited Liability Company Agreement of Solaris LLC. Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by any reporting person that it is the beneficial owner of any of the securities referred to herein for purposes of Section 13(d) of the Securities Exchange Act of 1934, as amended, or for any other purpose, and such beneficial ownership is expressly disclaimed.
(b)
Percent of class:
The information required by Item 4(b) is set forth in Row 11 of the cover pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
Based on 65,831,540 shares of Class A Common Stock of the Issuer issued and outstanding as of August 3, 2026 as reported in the Issuer's quarterly report on Form 10-Q for the fiscal quarter ended June 30, 2026, filed with the SEC on August 6, 2026 and 5,079,234 shares of Class A Common Stock issuable upon the exchange of shares of Class B Common Stock together with Solaris LLC Units as described above.
(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 pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
(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 pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
These securities are directly held by Yorktown Energy Partners X, L.P., a Delaware limited partnership. Yorktown X Company LP, a Delaware limited partnership, is the sole general partner of Yorktown X and Yorktown X Associates LLC, a Delaware limited liability company, is the sole general partner of Yorktown X Company. As a result, Yorktown X Company and Yorktown X Associates may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown X. Yorktown X Company and Yorktown X Associates disclaim beneficial ownership of the securities owned by Yorktown X in excess of its pecuniary interests therein.
(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 pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
(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 pages hereto for each Reporting Person and is incorporated herein by reference for each Reporting Person.
These securities are directly held by Yorktown Energy Partners X, L.P., a Delaware limited partnership. Yorktown X Company LP, a Delaware limited partnership, is the sole general partner of Yorktown X and Yorktown X Associates LLC, a Delaware limited liability company, is the sole general partner of Yorktown X Company. As a result, Yorktown X Company and Yorktown X Associates may be deemed to have the power to vote or direct the vote or to dispose or direct the disposition of the shares owned by Yorktown X. Yorktown X Company and Yorktown X Associates disclaim beneficial ownership of the securities owned by Yorktown X in excess of its pecuniary interests therein.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
Not Applicable
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:
Not Applicable
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.
YORKTOWN ENERGY PARTNERS X, L.P.
Signature:
/s/ Robert A. Signorino
Name/Title:
Robert A. Signorino/Manager of the General Partner of the General Partner
Date:
08/12/2026
YORKTOWN X COMPANY LP
Signature:
/s/ Robert A. Signorino
Name/Title:
Robert A. Signorino/Manager of the General Partner
