Exhibit 99.4

SELECT WATER SOLUTIONS, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED BALANCE SHEET

As of June 30, 2026

(in thousands)

The accompanying notes are an integral part of these unaudited pro forma condensed combined financial statements.

SELECT WATER SOLUTIONS, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the year ended December 31, 2025

(in thousands, except per share amounts)

SELECT WATER SOLUTIONS, INC.

UNAUDITED PRO FORMA CONDENSED COMBINED STATEMENT OF OPERATIONS

For the six months ended June 30, 2026

(in thousands, except per share amounts)

SELECT WATER SOLUTIONS, INC.

NOTES TO PRO FORMA CONDENSED COMBINED FINANCIAL STATEMENTS

($ in thousands, except share price)

NOTE 1—Basis of Presentation and Preliminary Purchase Price Allocation

Description of the transactions

On September 24, 2026, Select entered into a Membership Interest Purchase Agreement (the “MIPA”) to acquire 100% of the membership interests of Pilot Water Solutions LLC (“Pilot Water”) from its equity holders (the “Sellers”) (the “Pilot Water Acquisition”). In separate transactions, Select will issue the New Senior Notes and make a Revolver Draw. Select will use the proceeds of the New Financing to fund the cash consideration for the Pilot Water Acquisition, including the Payoff Amount, to repay its existing term loan and revolving credit facility, and to pay related fees and expenses.

Basis of presentation

The unaudited pro forma condensed combined financial statements have been prepared in accordance with Article 11 of Regulation S-X. The unaudited pro forma condensed combined balance sheet as of June 30, 2026 gives effect to the Pilot Water Acquisition and the New Financing as if they had occurred on June 30, 2026. The unaudited pro forma condensed combined statements of operations for the year ended December 31, 2025 and the six months ended June 30, 2026 give effect to them as if they had occurred on January 1, 2025. The Pilot Water Acquisition will be accounted for as a business combination under ASC 805, Business Combinations, with Select as the accounting acquirer. The unaudited pro forma condensed combined financial statements are presented for illustrative purposes only and do not necessarily indicate the financial position or results of operations that would have been achieved had the transactions occurred on the dates indicated, or that may be achieved in the future.

Consideration

The Equity Consideration is a fixed value of $100.0 million, payable in a number of shares of Select Class A common stock equal to $100.0 million divided by the 30-day volume-weighted average price prior to closing. The pro forma financial information assumes the issuance of 5,000,000 shares based on a price of $20.00 which is a reasonable estimate of the share price over the last 30 days. As the value of the Equity Consideration is fixed, changes in Select's share price prior to closing would change the number of shares issued but not the total consideration. A 10% increase or decrease in the share price would result in the issuance of approximately 4,545,455 or 5,555,556 shares, respectively. The effect on pro forma basic and diluted earnings per share would not be material.

Preliminary purchase price allocation

The following table summarizes the preliminary allocation of the estimated consideration to the assets acquired and liabilities assumed as of June 30, 2026, after giving effect to the Closing Distribution:

The purchase price allocation is preliminary and based on estimates and assumptions that are subject to change, and the final allocation may differ materially from the amounts presented. The fair values of property and equipment, identifiable intangible assets, asset retirement obligations, noncontrolling interests, the contingent payment and the Equity True-Up have not been finalized, and the final working capital adjustment, Sellers’ Transaction Expenses and Payoff Amount will be determined at closing. Completing the allocation requires final third-party valuations, Pilot Water’s closing balance sheet and the final closing statement under the MIPA. Select expects to finalize the allocation as soon as practicable, but no later than one year after the closing date.

NOTE 2—Adjustments to Unaudited Pro Forma Condensed Combined Balance Sheet

A            Reflects the reclassification of Pilot Water's other receivables into prepaid expenses and other current assets to conform to Select's balance sheet presentation.

B            Reflects the reclassification of certain of Pilot Water's accrued expenses and other current liabilities into various current liability classifications to conform to Select's balance sheet presentation.

C            Reflects the reclassification of Pilot Water's asset retirement obligation (“ARO”) liabilities into other long-term liabilities, as Select does not present a separate caption for ARO liabilities.

D            Reflects the use of a portion of the proceeds of the New Senior Notes (see Note E) to repay all outstanding indebtedness under Select's existing term loan and revolving credit facility, consisting of $62,500 of current portion of long-term debt, $187,500 of long-term debt, net, and $212 of accrued interest within accrued expenses and other current liabilities. Related unamortized debt issuance costs of $5,893, consisting of $2,641 within other long-term assets and $3,252 within long-term debt, net, were written off to accumulated deficit as a loss on extinguishment of debt. Select's agricultural loan of $12,938 is not repaid and remains outstanding.

E            Reflects the issuance of $800,000 of new senior unsecured notes (the “New Senior Notes”), reflected as an increase to cash and cash equivalents and long-term debt, net. The New Senior Notes offering is a separate transaction from the Pilot Water Acquisition. Its proceeds, together with the proceeds of the Revolver Draw described in Note F below, were used to fund a portion of the cash consideration for the Pilot Water Acquisition (from which Pilot Water’s related-party debt is repaid; see Notes H and N) and to repay Select's pre-transaction indebtedness (see Note D) (together, the New Senior Notes and the Revolver Draw, the “New Financing”).

F            Reflects a $62,000 draw on Select's revolving credit facility (the “Revolver Draw”), reflected as an increase to cash and cash equivalents and long-term debt, net, the proceeds of which were used together with the proceeds of the New Senior Notes to fund a portion of the transaction as described in Note E above.

G            Reflects $33,625 of fees paid in cash in connection with the New Financing, consisting of (i) $21,625 of debt issuance costs, of which $12,000 is presented as a reduction of long-term debt, net, and $9,625 relating to the Revolver Draw is capitalized within other long-term assets and amortized over the five-year term of the revolving credit facility; and (ii) a $12,000 bridge commitment fee, which is expensed and reflected as an increase to accumulated deficit (see Note JJ). The bridge commitment fee is nonrecurring and is reflected in interest expense in the pro forma statement of operations for the year ended December 31, 2025, with a related tax benefit of $2,760 (see Note KK).

H            Reflects total estimated consideration of $733,950 for the Pilot Water Acquisition (see Note 1), consisting of (i) $600,000 of cash (the “Base Cash Consideration”), reflected as a reduction to cash and cash equivalents, (ii) $100,000 of equity (the “Equity Consideration”), representing an estimated 5,000,000 shares of Select Class A common stock, reflected as an increase of $50 to Class A common stock and $99,950 to additional paid-in capital, (iii) $7,500 of additional cash consideration (the “Estimated Cash Amount”), reflected as a reduction to cash and cash equivalents, and (iv) $26,450 of contingent consideration payable, reflected within accrued expenses and other current liabilities. The contingent consideration payable consists of the estimated fair value of (a) a $15,000 contingent payment ($14,700) and (b) an estimated cash true-up payment (the “Equity True-Up”) ($11,750).

Equity True-Up - If Select’s 30-day VWAP six months after closing is below the 30-day VWAP Closing Share Price, Select will pay the Sellers in cash the shortfall multiplied by the shares issued as Equity Consideration, less dividends paid on those shares. The undiscounted outcome ranges from $0 to approximately $100,000, less dividends. Fair value was estimated using a Black-Scholes put on the $100,000 of equity consideration, struck at the $20.00 closing share price with a six-month term, 44.7% six-month historical volatility, a 4.0% risk-free rate and a 1.4% dividend yield.

The contingent payment is based on the achievement of a specific performance condition and was estimated by disounting the amount over 90 days (the period in which the specific performance condition should or should not be achieved). The range of the contingent payment is $0 - $15,000.

Subsequent changes in the fair value of the contingent payment and the Equity True-Up will be recognized in earnings and are not reflected in the unaudited pro forma combined financial statements.

I            Reflects goodwill of $94,429, calculated as total consideration of $733,950 less the preliminary estimated fair value of Pilot Water’s net assets acquired of $639,521, after giving effect to the $39,088 estimated Closing Distribution (see Note Q). Together with the elimination of Pilot Water’s historical goodwill of $29,469 (see Note L), the net adjustment to goodwill is $64,960. The purchase price allocation is preliminary and may change materially as the valuations are finalized (see Note 1).

J            Reflects the elimination of Pilot Water's historical property and equipment, gross, of $790,336 and related accumulated depreciation of $128,824 as of June 30, 2026, in connection with recording Pilot Water's property & equipment at preliminary estimated acquisition-date fair value.

K            Reflects the preliminary estimated fair value of Pilot Water's property and equipment of $633,145, reflected within property and equipment and including $63,200 of fixed assets subject to asset retirement obligations, together with the related preliminary estimated ARO liability of $63,200. The $39,481 adjustment to other long-term liabilities increases Pilot Water’s historical ARO liability of $23,719 (reclassified in Note C) to its preliminary estimated fair value of $63,200. Its main assumptions are the estimated costs to plug and abandon Pilot Water’s disposal wells, the discount rate using a credit-adjusted risk free rate, and the expected timing of those costs over approximately 15 years.

L             Reflects the elimination of Pilot Water's historical goodwill of $29,469 and other intangible assets, net, of $66,832 in connection with the preliminary estimated accounting for the transaction.

M            Reflects the preliminary estimated fair value of $60,000 of identifiable intangible assets recognized within other intangible assets.

N            Reflects the repayment at closing of Pilot Water's related-party revolving credit facility with Pilot Travel Centers LLC, including accrued interest. The credit facility's carrying value of $428,511, net of $875 of unamortized deferred financing costs, is removed from long-term debt, net, and the related accrued interest of $2,402 is removed from accrued expenses and other current liabilities. The repayment of $431,788, consisting of principal of $429,386 and accrued interest of $2,402 (the "Payoff Amount"), is funded from the $600,000 Base Cash Consideration.

O            Reflects the elimination of Pilot Water's historical equity in connection with the application of the acquisition method of accounting, consisting of additional paid-in capital of $346,523, retained earnings of $5,341 and noncontrolling interests of $981.

P            Reflects adjustments to noncontrolling interests consisting of (i) the preliminary estimated fair value of $1,000 of noncontrolling interests in certain of Pilot Water's consolidated well partnerships held by third parties, and (ii) a $5,606 reclassification from additional paid-in capital to noncontrolling interests to reflect the change in the relative ownership of SES Holdings, LLC (“OpCo”) between Select and the holders of Class B common stock resulting from the issuance of the Equity Consideration. After giving effect to the issuance of 5,000,000 shares of Class A common stock, the holders of Class B common stock are assumed to own approximately 7.79% of OpCo. The adjustment to noncontrolling interests is calculated as follows:

The $5,606 reclassification adjusts noncontrolling interests from $89,169 (Select’s historical noncontrolling interests of $88,169 plus the $1,000 above) to $94,775, or 7.79% of pro forma total equity of $1,216,627.

Q            Reflects the distribution to the Sellers before closing of $39,088 (the "Closing Distribution"), representing the excess of Pilot Water's cash and cash equivalents of $46,588 over the $7,500 Pilot Water retains at closing, reflected as a reduction to cash and cash equivalents. The Closing Distribution reduces the net assets acquired and therefore increases goodwill by the same amount (see Note I).

NOTE 3—Adjustments to Unaudited Pro Forma Condensed Combined Statements of Operations

AA Certain reclassifications have been made to Pilot Water's historical statement of operations to conform with Select's presentation. Pilot Water's historical statement of operations includes gains/losses on sales of property and equipment in costs of revenue whereas Select reports these as its own line item as part of Other income (expense) in the statement of operations. Pilot Water's historical statement of operations includes interest income in Other whereas Select nets interest income with interest expense. Pilot Water’s historical statement of operations also presents interest expense on its related-party credit facility ($32,253 for the year ended December 31, 2025 and $14,847 for the six months ended June 30, 2026) as a separate line item, which has been reclassified to interest expense, net.

BB            Certain reclassifications have been made to Pilot Water's historical statement of operations to conform with Select's presentation. Pilot Water's historical statement of operations includes portions of a $13,037 legal settlement within costs of revenue ($5,877) and impairments and abandonments ($7,160) whereas Select has chosen to reflect the entire settlement as its own line item as part of Other income (expense) in the statement of operations.

CC            To eliminate Pilot Water's historical depreciation, amortization and accretion expense.

DD            Represents depreciation expense associated with the preliminary estimated fair value and useful lives of Pilot Water's property and equipment.

EE            Represents depreciation expense associated with the preliminary estimated fair value of Pilot Water's property and equipment subject to AROs.

FF            Represents accretion expense associated with the preliminary estimated ARO liabilities of Pilot Water's property and equipment.

GG            Reflects amortization expense associated with preliminary estimated intangible assets recorded in this transaction.

HH Reflects $4,000 of estimated transaction costs to be incurred by Select in connection with the Pilot Water Acquisition after June 30, 2026, consisting of advisory, legal, accounting and other professional fees. These costs are not reflected in Select’s historical financial statements. They are reflected as increases to accrued expenses and other current liabilities and accumulated deficit in the pro forma condensed combined balance sheet and within selling, general and administrative expense in the pro forma condensed combined statement of operations for the year ended December 31, 2025. These costs are nonrecurring. No tax benefit has been recognized.

II            To eliminate historical interest expense associated with Pilot Water’s legacy debt and substantially all of Select’s debt outstanding prior to the New Senior Notes offering, the proceeds of which are used to repay Select’s existing term loan and revolving credit facility (see Note D). For the six months ended June 30, 2026, only $0.1 million of historical interest expense related to Select’s agricultural loan remains.

JJ             Represents estimated interest expense associated with the New Senior Notes and the Revolver Draw, including amortization of deferred financing costs and, for the year ended December 31, 2025, a nonrecurring $12,000 bridge commitment fee (see Note G). Such adjustment assumes an effective interest rate for illustrative purposes only as if the issuance occurred on January 1, 2025. Assuming no change in the amount outstanding, the impact on the pro forma interest expense of a 1/8% increase or decrease in the assumed interest rate would be approximately $1 million per year. The estimated interest expense set forth above is solely for illustrative purposes and reflects certain assumptions with respect to the New Financing.

KK Select has assumed a 23% tax rate, consisting of the 21% U.S. federal statutory rate and an estimated 2% blended state rate, net of federal benefit when estimating the tax impacts of the appropriate pro forma adjustments. No tax effect has been recorded on the depreciation and accretion expense related to AROs (EE and FF), as the related tax deductions arise when costs to plug wells are incurred , or on the transaction costs in Note HH, which are assumed to be nondeductible. As Pilot Water is a pass-through entity for U.S. federal income tax purposes, its historical statements of operations do not include federal income tax expense; accordingly, the tax effect of Pilot Water’s historical pre-tax income is included below. The effective tax rate of the combined company could be significantly different from what is presented in these unaudited pro forma condensed combined financial statements for a variety of reasons, including post-acquisition activities. The tax impact of the pro forma adjustments has been calculated as follows ($ in thousands):

LL             Reflects the allocation of the pro forma adjustments to the noncontrolling interests held by the holders of Class B common stock, based on their weighted-average ownership of OpCo of 12.92% for the year ended December 31, 2025 and 10.45% for the six months ended June 30, 2026, after giving effect to the shares assumed issued in the Pilot Water Acquisition. The allocation is applied to the pre-tax pro forma adjustments.

MM             Represents the adjusted weighted-average basic shares outstanding, calculated as follows:

(1) Calculated as the $100,000 Equity Consideration divided by an assumed 30-day VWAP Closing Share Price of $20.00. See Note 1 for the sensitivity of the share count to changes in Select’s share price.

NN            Represents the adjusted weighted-average diluted shares outstanding, calculated as follows:

OO            Select has assumed a 23% tax rate, consisting of the 21% U.S. federal statutory rate and an estimated 2% blended state rate, net of federal benefit, when estimating the tax impacts of the appropriate pro forma adjustments. No tax effect has been recorded on the depreciation and accretion expense related to AROs (EE and FF), as the related tax deductions arise when costs to plug wells are incurred, or on the transaction costs in Note HH, which are assumed to be nondeductible. As Pilot Water is a pass-through entity for U.S. federal income tax purposes, its historical statements of operations do not include federal income tax expense; accordingly, the tax effect of Pilot Water’s historical pre-tax income is included below. The effective tax rate of the combined company could be significantly different from what is presented in these unaudited pro forma condensed combined financial statements for a variety of reasons, including post-acquisition activities. The tax impact of the pro forma adjustments has been calculated as follows ($ in thousands):

PP            Represents the adjusted weighted-average basic shares outstanding, calculated as follows:

QQ            Represents the adjusted weighted-average diluted shares outstanding, calculated as follows: