Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: KEEP THIS PORTION FOR YOUR RECORDS DETACH AND RETURN THIS PORTION ONLYTHIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED. V93259-P49050 For Against Abstain For Against Abstain ! !! ! !! ! !! ! !! ! !! ! !! NATURAL GAS SERVICES GROUP, INC. 601 STATE ST, SUITE 400 SOUTHLAKE, TX 76092 NATURAL GAS SERVICES GROUP, INC. Nominees: 4. Approve the redomestication of the Company from Colorado to Texas by conversion; and 5. To transact such other business as may properly be presented at the meeting, or at any adjournment(s) of the meeting. Please sign exactly as your name(s) appear(s) hereon. When signing as attorney, executor, administrator, or other fiduciary, please give full title as such. Joint owners should each sign personally. All holders must sign. If a corporation or partnership, please sign in full corporate or partnership name by authorized officer. 2. Advisory vote to approve the compensation of our named executive officers; 3. Ratification of the appointment of Ham, Langston & Brezina LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026; and 1. Election of Directors The Board of Directors recommends you vote FOR the following: The Board of Directors recommends you vote FOR proposals 2, 3 and 4. 1a. J. Anthony Gallegos Jr. 1b. Justin C. Jacobs 1c. John E. Jackson VOTE BY INTERNET Before The Meeting - Go to www.proxyvote.com or scan the QR Barcode above Use the Internet to transmit your voting instructions and for electronic delivery of information up until 11:59 p.m. Eastern Daylight Time on June 9, 2026. Have your proxy card in hand when you access the web site and follow the instructions to obtain your records and to create an electronic voting instruction form. During The Meeting - Go to www.virtualshareholdermeeting.com/NGS2026 You may attend the meeting via the Internet and vote during the meeting. Have the information that is printed in the box marked by the arrow available and follow the instructions. VOTE BY PHONE - 1-800-690-6903 Use any touch-tone telephone to transmit your voting instructions up until 11:59 p.m. Eastern Daylight Time on June 9, 2026. Have your proxy card in hand when you call and then follow the instructions. VOTE BY MAIL Mark, sign and date your proxy card and return it in the postage-paid envelope we have provided or return it to Vote Processing, c/o Broadridge, 51 Mercedes Way, Edgewood, NY 11717. SCAN TO VIEW MATERIALS & VOTEw
V93260-P49050 Important Notice Regarding the Availability of Proxy Materials for the Annual Meeting: The Notice and Proxy Statement and 10-K/Annual Report Combo are available at www.proxyvote.com. NATURAL GAS SERVICES GROUP, INC. THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORS ANNUAL MEETING OF SHAREHOLDERS JUNE 10, 2026. The shareholder(s) hereby appoint(s) Justin C. Jacobs and Ian M. Eckert, or either of them, as proxies, each with the power to appoint his substitute, and hereby authorize(s) them to represent and to vote, as designated on the reverse side of this ballot, all of the shares of Common Stock of NATURAL GAS SERVICES GROUP, INC. that the shareholder(s) is/are entitled to vote at the Annual Meeting of Shareholders to be held at 8:00 AM, CDT on June 10, 2026, and any adjournment or postponement thereof. THIS PROXY, WHEN PROPERLY EXECUTED, WILL BE VOTED AS DIRECTED BY THE SHAREHOLDER(S). IF NO SUCH DIRECTIONS ARE MADE, THIS PROXY WILL BE VOTED FOR THE ELECTION OF THE NOMINEES LISTED ON THE REVERSE SIDE FOR THE BOARD OF DIRECTORS AND THE BOARD OF DIRECTORS RECOMMENDS YOU VOTE FOR PROPOSALS 2, 3 AND 4. IF ANY OTHER MATTER PROPERLY COMES BEFORE THE MEETING, THE PERSONS NAMED IN THE PROXY WILL VOTE IN THEIR DISCRETION. PLEASE MARK, SIGN, DATE AND RETURN THIS PROXY CARD PROMPTLY USING THE ENCLOSED REPLY ENVELOPE. Continued and to be signed on reverse side