Zartler William A

SEC source: 0001628280-26-014091 · wk-form4_1772577783.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Chairman and Co-CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,314,883

F2 · shares: Reflects the vesting and settlement of shares that relate to multiple Performance-Based Restricted Stock Unit (PSU) awards granted pursuant to the Solaris Energy Infrastructure, Inc. Long Term Incentive Plan. The PSUs which were originally granted on March 1, 2023, March 1, 2024 and March 1, 2025 vested and were settled based on the Issuer's level of achievement with respect to the applicable performance goals

F3 · balance_after: Includes 387,755 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001628280-26-014091 · wk-form4_1772577783.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Chairman and Co-CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,199,227

F1 · shares: Restricted Stock Award granted pursuant to the Solaris Energy Infrastructure, Inc. Long Term Incentive Plan on the date indicated. The award vests in three equal installments on the first three anniversaries of the grant date.

SEC source: 0001193125-25-240631 · ownership.xml · derivative · entry 8

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Class A Common Stock · 56,497 shares

Expires 2027-12-31

F5 · price: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

F5 · derivative.exercise_date: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

SEC source: 0001193125-25-240631 · ownership.xml · derivative · entry 7

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Class A Common Stock · 162,712 shares

Expires 2026-12-31

F5 · price: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

F5 · derivative.exercise_date: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

SEC source: 0001193125-25-240631 · ownership.xml · derivative · entry 6

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Class A Common Stock · 139,473 shares

Expires 2025-12-31

F5 · price: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

F5 · derivative.exercise_date: At the Effective Time, each outstanding award of performance-vesting restricted stock units ("Issuer PSU Awards") held by the Reporting Person was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Aris PSU Award (assuming that any performance-based vesting conditions applicable to such Issuer PSU Award were achieved at the greater of (x) the target level of performance and (y) the greater of the actual level of performance through (1) August 13, 2025, and (2) the Effective Time), multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid dividend equivalents.

SEC source: 0001193125-25-240631 · ownership.xml · derivative · entry 5

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Class A Common Stock · 1,064,617 shares

Expires not disclosed

F1 · derivative.exercise_price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.exercise_price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · derivative.exercise_date: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.exercise_date: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · derivative.expiration_date: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.expiration_date: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F4 · ownership.nature: Represents securities held by Solaris Energy Capital, LLC ("Solaris Energy Capital"). The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the securities held through Solaris Energy Capital in his sole discretion. As a result, the Reporting Person may be deemed to beneficially own all of the securities owned by Solaris Energy Capital. The Reporting Person disclaims beneficial ownership of the shares held by Solaris Energy Capital in excess of his pecuniary interest therein.

SEC source: 0001193125-25-240631 · ownership.xml · derivative · entry 4

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Class A Common Stock · 488,474 shares

Expires not disclosed

F1 · derivative.exercise_price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.exercise_price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · derivative.exercise_date: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.exercise_date: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · derivative.expiration_date: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · derivative.expiration_date: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

SEC source: 0001193125-25-240631 · ownership.xml · nonDerivative · entry 3

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F1 · kind: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · kind: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · shares: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · shares: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F3 · shares: This amount includes 202,837 shares of Issuer Class A Common Stock subject to awards of time-vesting restricted stock units ("Issuer RSU Awards") held by the Reporting Person. At the Effective Time, each Issuer RSU Award was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Issuer RSU Award, multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid cash-based dividend equivalents.

F1 · price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F4 · ownership.nature: Represents securities held by Solaris Energy Capital, LLC ("Solaris Energy Capital"). The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the securities held through Solaris Energy Capital in his sole discretion. As a result, the Reporting Person may be deemed to beneficially own all of the securities owned by Solaris Energy Capital. The Reporting Person disclaims beneficial ownership of the shares held by Solaris Energy Capital in excess of his pecuniary interest therein.

SEC source: 0001193125-25-240631 · ownership.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · kind: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · kind: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F1 · shares: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · shares: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F3 · shares: This amount includes 202,837 shares of Issuer Class A Common Stock subject to awards of time-vesting restricted stock units ("Issuer RSU Awards") held by the Reporting Person. At the Effective Time, each Issuer RSU Award was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Issuer RSU Award, multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid cash-based dividend equivalents.

F1 · price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

SEC source: 0001193125-25-240631 · ownership.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

F1 · kind: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · kind: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F3 · kind: This amount includes 202,837 shares of Issuer Class A Common Stock subject to awards of time-vesting restricted stock units ("Issuer RSU Awards") held by the Reporting Person. At the Effective Time, each Issuer RSU Award was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Issuer RSU Award, multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid cash-based dividend equivalents.

F1 · shares: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · shares: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F3 · shares: This amount includes 202,837 shares of Issuer Class A Common Stock subject to awards of time-vesting restricted stock units ("Issuer RSU Awards") held by the Reporting Person. At the Effective Time, each Issuer RSU Award was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Issuer RSU Award, multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid cash-based dividend equivalents.

F1 · price: As of the effective time (the "Effective Time") of the transactions contemplated by the Agreement and Plan of Merger entered into on August 6, 2025, by and among the Issuer, Western Midstream Partners, LP ("Parent"), Arrakis OpCo Merger Sub LLC, Arrakis Holdings Inc., Arrakis Unit Merger Sub LLC, Arrakis Cash Merger Sub LLC and Aris Water Holdings, LLC ("Aris OpCo"), each issued and outstanding share of the Issuer's Class A common stock, par value $0.01 per share ("Issuer Class A Common Stock") and each Aris OpCo Unit and a corresponding share of Issuer Class B common stock, par value $0.01 per share ("Issuer Class B Common Stock"), held by the Reporting Person as of immediately prior to the Effective Time, was converted into the right to receive, pursuant to an election made by the Reporting Person, one of the following forms of consideration:

F2 · price: cont'd from Footnote 1: (i) $7.00 in cash (without interest) and 0.450 common units representing limited partnership interests in Parent ("Parent Common Units"); (ii) $25.00 in cash (without interest); (iii) 0.625 Parent Common Units ("Common Unit Election Consideration"), or (iv) in the event of the Reporting Person's failure to timely deliver an election, the Common Unit Election Consideration.

F3 · price: This amount includes 202,837 shares of Issuer Class A Common Stock subject to awards of time-vesting restricted stock units ("Issuer RSU Awards") held by the Reporting Person. At the Effective Time, each Issuer RSU Award was converted into the right to receive an amount in cash equal to (i) the total number of shares of Issuer Class A Common Stock subject to such Issuer RSU Award, multiplied by (ii) $25.00, plus an additional amount in cash equal to any accrued but unpaid cash-based dividend equivalents.

SEC source: 0001415889-25-023973 · form4-09092025_080917.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,049,227

F1 · price: The reported price in Column 4 is a weighted average purchase price. These shares were purchased in multiple transactions at prices ranging from $24.80 to $24.84 per share. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the U.S. Securities and Exchange Commission (the "SEC"), upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

F2 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-25-014050 · form4-05222025_030543.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,039,227

F1 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-25-007362 · form4-03072025_080305.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,029,227

F1 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001865187-25-000030 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 584,270

F1 · shares: Represents restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) one-third on March 1, 2026, (ii) one-third on March 1, 2027, and (iii) one-third on March 1, 2028.

SEC source: 0001415889-25-007343 · form4-03072025_060321.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,019,227

F1 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-25-007591 · form4a-03102025_110309.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,019,227

F1 · kind: The original Form 4, filed on March 7, 2025, is being amended by this Form 4 amendment solely to correct an administrative error, which misreported the purchase of 10,000 shares of Class A Common Stock using transaction code of "A" when in fact this was an open market purchase with transaction code of "P".

F2 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001865187-25-000016 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 500,545

F1 · shares: Surrender of shares in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001415889-25-006638 · form4-03042025_100356.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,009,227

F2 · shares: Represents shares withheld by the Company to satisfy tax withholding obligations upon the vesting of previously granted Restricted Stock Awards.

F3 · balance_after: Includes 450,381 shares of Class A common stock from previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-25-006638 · form4-03042025_100356.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,090,341

F1 · shares: Restricted Stock Award pursuant to the Solaris Energy Infrastructure, Inc. Long Term Incentive Plan. The award vests in three equal installments on the first three anniversaries of the grant date.

SEC source: 0001865187-25-000006 · form4.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 542,090

F2 · shares: Surrender of shares in payment of tax withholding due as a result of the settlement of vested PSUs.

SEC source: 0001865187-25-000006 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 558,589

F1 · shares: Shares of Class A common stock received upon vesting of performance-based restricted stock units ("PSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan.

SEC source: 0001865187-24-000053 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 503,654

F1 · shares: Surrender of shares on December 16, 2024 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001865187-24-000043 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 530,666

F1 · shares: Surrender of shares on October 22, 2024 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001865187-24-000012 · form4.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 543,531

F2 · shares: Represents 122,034 restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) one-third on March 1, 2025, (ii) one-third on March 1, 2026, and (iii) one-third on March 1, 2027

SEC source: 0001865187-24-000012 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 421,497

F1 · shares: Surrender of shares on March 1, 2024 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001415889-24-006850 · form4-03052024_110354.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 864,963

F3 · shares: Represents shares withheld by the Company to satisfy tax withholding obligations upon the vesting of previously granted Restricted Stock Awards and Performance-Based Restricted Stock Awards.

F4 · balance_after: Includes 436,717 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-24-006850 · form4-03052024_110354.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 917,551

F1 · shares: Includes 262,500 shares from Restricted Stock Award granted pursuant to the Solaris Oilfield Infrastructure, Inc. Long Term Incentive Plan on the date indicated. The award vests in three equal annual installments on the first three anniversaries of the grant date.

F2 · shares: Includes 4,911 shares vested from Performance-Based Restricted Stock Unit (PSU) Agreement pursuant to the Solaris Oilfield Infrastructure, Inc. Long Term Incentive Plan. The PSUs, which were originally granted on March 1, 2023, vested based on the issuer's level of achievement with respect to relative total stockholder return during the applicable performance period (which began on January 1, 2023 and ended on December 31, 2023).

SEC source: 0001865187-23-000071 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 442,623

F1 · shares: Surrender of shares on December 18, 2023 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001865187-23-000054 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 468,928

F1 · shares: Surrender of shares on October 23, 2023 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001865187-23-000019 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 476,889

F1 · shares: Represents 113,255 restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) one-third on March 1, 2024, (ii) one-third on March 1, 2025, and (iii) one-third on March 1, 2026.

SEC source: 0001865187-23-000009 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 363,634

F1 · shares: Surrender of shares on March 1, 2023 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001104659-23-028544 · tm238525-1_4seq1.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Chairman and CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 650,140

F2 · shares: Represents shares withheld by the Company to satisfy tax withholding obligations upon the vesting of previously granted Restricted Stock Awards.

F3 · balance_after: Includes 333,446 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001104659-23-028544 · tm238525-1_4seq1.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Chairman and CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 688,175

F1 · shares: Restricted Stock Award pursuant to the Solaris Oilfield Infrastructure, Inc. Long Term Incentive Plan. The award vests in three equal annual installments on the first three anniversaries of the grant date.

SEC source: 0001140361-22-046096 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 370,575

F1 · shares: Surrender of shares on December 16, 2022 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001415889-22-012754 · form4-12192022_101257.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 538,175

F1 · balance_after: Includes 309,343 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001140361-22-038401 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 397,587

F1 · shares: Surrender of shares on October 24, 2022 in payment of tax withholding due as a result of the settlement of vested restricted stock units.

SEC source: 0001415889-22-009706 · form4-09162022_040902.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 561,175

F1 · balance_after: Includes 309,343 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-22-004783 · form4-05092022_030535.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 551,175

F1 · balance_after: Includes 309,343 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-22-002158 · form4-03022022_020343.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 544,175

F2 · shares: Represents shares withheld by the Company to satisfy tax withholding obligations upon the vesting of previously granted Restricted Stock Awards.

F3 · balance_after: Includes 309,343 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-22-002158 · form4-03022022_020343.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 566,307

F1 · shares: Restricted Stock Award pursuant to the Solaris Oilfield Infrastructure, Inc. Long Term Incentive Plan. The award vests in three equal annual installments on the first three anniversaries of the grant date.

SEC source: 0001140361-22-007700 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 418,153

F1 · shares: Represents 81,452 restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) one-third on March 1, 2023, (ii) one-third on March 1, 2024, and (iii) one-third on March 1, 2025.

SEC source: 0001140361-21-042276 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 336,701

F1 · shares: Represents 205,931 restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) one-third on December 16, 2022, (ii) one-third on December 16, 2023, and (iii) one-third on December 16, 2024.

SEC source: 0001415889-21-005783 · form4-12082021_011235.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 343,661

F1 · price: The Price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.60 to $6.65, inclusive. The reporting person undertakes to provide Solaris Oilfield Infrastructure, Inc., any security holder of Solaris Oilfield Infrastructure, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote to the Form 4.

F2 · balance_after: Includes 171,711 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001415889-21-005447 · form4-11232021_021128.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · CHAIRMAN AND CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 333,661

F1 · balance_after: Includes 171,711 shares of Class A common stock subject to previously granted Restricted Stock Awards that remain subject to vesting.

SEC source: 0001140361-21-035829 · form4.xml · derivative · entry 3

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Class A Common Stock · 0 shares

Expires not disclosed

F3 · shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners will be converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC will distribute to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange.

F4 · shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it receives pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person will be reported on an amendment to this Form 4 as soon as practicable once the number of Solaris LLC Units and shares of Class B common stock are determined pursuant to the Solaris LLC Agreement.

F6 · derivative.exercise_date: Subject to certain limitations and exceptions described in the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are redeemable from time to time for shares of Class A common stock of the Issuer (on a one-for-one basis, subject to conversion rate adjustments for stock splits, stock dividends and reclassification and other similar transactions).

F6 · derivative.expiration_date: Subject to certain limitations and exceptions described in the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are redeemable from time to time for shares of Class A common stock of the Issuer (on a one-for-one basis, subject to conversion rate adjustments for stock splits, stock dividends and reclassification and other similar transactions).

F3 · derivative.underlying_shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners will be converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC will distribute to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange.

F4 · derivative.underlying_shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it receives pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person will be reported on an amendment to this Form 4 as soon as practicable once the number of Solaris LLC Units and shares of Class B common stock are determined pursuant to the Solaris LLC Agreement.

F3 · balance_after: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners will be converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC will distribute to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange.

F4 · balance_after: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it receives pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person will be reported on an amendment to this Form 4 as soon as practicable once the number of Solaris LLC Units and shares of Class B common stock are determined pursuant to the Solaris LLC Agreement.

F5 · ownership.nature: Represents shares held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion. The Reporting Person disclaims beneficial ownership of the shares held by Solaris Energy Capital in excess of his pecuniary interest therein.

SEC source: 0001140361-21-035829 · form4.xml · nonDerivative · entry 2

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

F2 · security: Each share of Class B common stock has no economic rights but entitles its holder to one vote on all matters to be voted on by stockholders generally.

F3 · shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners will be converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC will distribute to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange.

F4 · shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it receives pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person will be reported on an amendment to this Form 4 as soon as practicable once the number of Solaris LLC Units and shares of Class B common stock are determined pursuant to the Solaris LLC Agreement.

F3 · balance_after: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners will be converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC will distribute to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange.

F4 · balance_after: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it receives pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person will be reported on an amendment to this Form 4 as soon as practicable once the number of Solaris LLC Units and shares of Class B common stock are determined pursuant to the Solaris LLC Agreement.

F5 · ownership.nature: Represents shares held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion. The Reporting Person disclaims beneficial ownership of the shares held by Solaris Energy Capital in excess of his pecuniary interest therein.

SEC source: 0001140361-21-035829 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 130,770

F1 · shares: Represents 130,770 restricted stock units ("RSUs") granted under the Aris Water Solutions, Inc. 2021 Equity Incentive Plan. Each RSU represents the right to receive one share of the Issuer's Class A common stock. The RSUs will vest in the following installments: (i) 50% on October 22, 2022, (ii) 25% on October 22, 2023, and (iii) 25% on October 22, 2024.

SEC source: 0001140361-21-037300 · form4.xml · derivative · entry 2

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 1,553,091

Underlying: Class A Common Stock · 1,553,091 shares

Expires not disclosed

F2 · shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners were converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC distributed to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange (the "VWAP").

F3 · shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it received pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person was determined on November 5, 2021 based on the VWAP.

F5 · derivative.exercise_date: Subject to certain limitations and exceptions described in the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are redeemable from time to time for shares of Class A common stock of the Issuer (on a one-for-one basis, subject to conversion rate adjustments for stock splits, stock dividends and reclassification and other similar transactions).

F5 · derivative.expiration_date: Subject to certain limitations and exceptions described in the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are redeemable from time to time for shares of Class A common stock of the Issuer (on a one-for-one basis, subject to conversion rate adjustments for stock splits, stock dividends and reclassification and other similar transactions).

F2 · derivative.underlying_shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners were converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC distributed to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange (the "VWAP").

F3 · derivative.underlying_shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it received pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person was determined on November 5, 2021 based on the VWAP.

F2 · balance_after: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners were converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC distributed to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange (the "VWAP").

F3 · balance_after: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it received pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person was determined on November 5, 2021 based on the VWAP.

F4 · ownership.nature: Represents securities held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion.

SEC source: 0001140361-21-037300 · form4.xml · nonDerivative · entry 1

Zartler William A · CIK 0001520378 · Director · Founder and Executive Chairman

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 1,553,091

F1 · security: Each share of Class B common stock has no economic rights but entitles its holder to one vote on all matters to be voted on by stockholders generally.

F2 · shares: Immediately prior to closing of the Issuer's initial public offering, the Fourth Amended and Restated Limited Liability Company Agreement of Solaris Midstream Holdings, LLC ("Solaris LLC"), of which the Issuer is the managing member, became effective (the "Solaris LLC Agreement"). Pursuant to the Solaris LLC Agreement, (i) all of the membership interests in Solaris LLC held by its existing owners were converted into a single class of units in Solaris LLC ("Solaris LLC Units") and (ii) Solaris LLC distributed to its members one share of Class B common stock for each Solaris LLC Unit held by such members, in each case based on the average of the volume weighted average price of shares of the Issuer's Class A common stock for the 10 trading days commencing with the date of the initial listing of the Issuer's Class A common stock on the New York Stock Exchange (the "VWAP").

F3 · shares: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it received pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person was determined on November 5, 2021 based on the VWAP.

F3 · balance_after: The beneficial ownership interests of the Reporting Person are represented by limited liability company interests in Solaris Midstream Investment, LLC ("Solaris Investment"), which has advised the Issuer that it intends to distribute all of the Solaris LLC Units and shares of the Issuer's Class B common stock it received pursuant to the Solaris LLC Agreement to its members, including Solaris Energy Capital, LLC ("Solaris Energy Capital"), a company controlled by the Reporting Person. Solaris Investment is expected to be wound up and dissolved following the foregoing distribution. The number of Solaris LLC Units and shares of Class B common stock beneficially owned by the Reporting Person was determined on November 5, 2021 based on the VWAP.

F4 · balance_after: Represents securities held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion.

F4 · ownership.nature: Represents securities held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion.

SEC source: 0001179110-21-003279 · edgar.xml · derivative · entry 7

Zartler William A · CIK 0001520378 · Director · Chairman and CEO · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 3,513,496

Underlying: Class A Common Stock · 400,000 shares

Expires not disclosed

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F6 · derivative.exercise_price: Subject to the terms of the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are exchangeable from time to time for shares of Class A common stock of the Issuer.

F6 · price: Subject to the terms of the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are exchangeable from time to time for shares of Class A common stock of the Issuer.

F6 · derivative.exercise_date: Subject to the terms of the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are exchangeable from time to time for shares of Class A common stock of the Issuer.

F6 · derivative.expiration_date: Subject to the terms of the Solaris LLC Agreement, the Solaris LLC Units (together with a corresponding number of shares of Class B common stock) are exchangeable from time to time for shares of Class A common stock of the Issuer.

F5 · ownership.nature: Represents shares held by Solaris Energy Capital. The Reporting Person is the sole member of Solaris Energy Capital and has the authority to vote or dispose of the shares held by Solaris Energy Capital in his sole discretion. The Reporting Person disclaims beneficial ownership of the shares held by Solaris Energy Capital in excess of his pecuniary interest therein.