NATURAL GAS SERVICES GROUP INC

The results of operations attributable to the Flatrock Acquisition have been included in our Condensed Consolidated Financial Statements from the Acquisition Date through June 30, 2026. Total revenue attributable to the net assets acquired from Flatrock from the Acquisition Date through June 30, 2026 was $2.2 million and pre-tax earnings attributable to the assets acquired and liabilities assumed since the Acquisition Date was $0.8 million.

Transaction costs

In connection with the Flatrock Acquisition, we engaged certain advisors and consultants to assist us with various activities to develop, execute and report the transaction. A substantial portion of costs were incurred during the three months ended June 30, 2026 and we anticipate additional transaction costs to be incurred during the third quarter of 2026, primarily attributable to advisory costs associated with the valuation, purchase price allocation and financial reporting. The following table summarizes transaction costs, primarily legal and diligence, directly attributable to the Flatrock Acquisition incurred during the three months ended June 30, 2026 which was recorded in selling, general and administrative expenses:

(1) Includes legal, business diligence, financial advisory and other consulting fees.

Unaudited Pro forma Financial Information

The unaudited supplemental pro forma financial information for the three and six months ended June 30, 2026 was derived by adjusting our historical financial statements in order to give effect to the Flatrock assets acquired and liabilities assumed as though the Flatrock Acquisition occurred as of January 1, 2025 and reflects the following:

•the application of our accounting policies to reflect the changes in depreciation and amortization attributable to the acquired rental equipment, property and equipment and intangible assets;

•the incremental interest expense resulting from borrowings under the Credit Facility to fund the cash component of the consideration transferred;

•the income tax effects of the adjustments described above based on our blended statutory tax rate.

The unaudited pro forma financial information presented below is presented for informational purposes only and is not necessarily indicative of the results of operations that would have occurred had the Flatrock Acquisition been consummated at the beginning of the period presented nor is it necessarily indicative of our future results of operations. Future results may vary significantly from the results reflected in this unaudited pro forma financial information.