PERFORMANCE-BASED RESTRICTED STOCK AWARD AGREEMENT

Name of Grantee (the “Grantee”): Brian Shepherd

Date of Performance-Based Restricted Stock Award (the “Award Date”): December 10, 2024

Number of Target Shares Covered by Performance-Based Restricted Stock Award (the “Target Shares”): 74,475

This Performance-Based Restricted Stock Award Agreement (this “Agreement”) is entered into as of the Award Date by and between CSG SYSTEMS INTERNATIONAL, INC., a Delaware corporation (the “Company”), and Grantee named above.

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WHEREAS, the Company has adopted an Amended and Restated 2005 Stock Incentive Plan, as may be amended from time to time (the “Plan”) which is administered by the Board of Directors of the Company (the “Board”);

WHEREAS, pursuant to the Plan, effective on the Award Date the Board granted to Grantee a Performance-Based Restricted Stock Award (the “Award”) covering (i) the number of Target Shares of the Common Stock of the Company (the “Common Stock”) set forth above and (ii) the right to receive additional shares of Common Stock (the “Overperformance Shares” and collectively with the Target Shares, the “Award Shares”) upon vesting in accordance with Section 2; and

WHEREAS, the Company is executing this Agreement with Grantee for the purpose of setting forth the terms and conditions of the Award made by the Board to Grantee effective on the Award Date.

NOW, THEREFORE, in consideration of the premises and the covenants and conditions contained herein, the Company and Grantee agree as follows:

Award Shares are divided into four (4) vesting tranches (each, a “Tranche”), with the Target Shares vesting 50% in Tranches 1 and 2 and the Overperformance Shares vesting 50% in Tranches 3 and 4. Each Tranche may vest, on a Service Vesting Date designated below, if both performance and service conditions are met during the Performance Period. If a Tranche meets its performance condition prior to meeting its service condition, it will vest on its Service Vesting Date. If a Tranche meets its service condition prior to meeting its performance condition, it will vest upon meeting its performance condition, provided that Grantee has remained in continuous service through the date that the performance condition was met. Except as otherwise provided in this Agreement, each Tranche will vest as a whole or not at all. The number of Award Shares eligible to vest in each Tranche based on the related performance and service conditions are set forth below:

Subject to the provisions of Section 17, upon a Termination of Employment of Grantee, all of the rights and interests of Grantee in any of the Award Shares which have not vested in Grantee pursuant to Section 2 prior to such Termination of Employment of Grantee automatically will completely and forever terminate; and, at the direction of the Company, the Transfer Agent will remove from the Restricted Stock Account and cancel all of those unvested Target Shares and any unvested Overperformance Shares shall be automatically forfeited. For purposes of this Agreement, a “Termination of Employment” of Grantee means the effective time when the employer-employee relationship between Grantee and the Company terminates for any reason whatsoever. In determining the existence of continuous employment of Grantee by the Company or the existence of an employer-employee relationship between Grantee and the Company for purposes of this Agreement, the term “Company” will include a Subsidiary (as defined in the Plan); and neither a transfer of Grantee from the employ of the Company to the employ of a Subsidiary nor the transfer of Grantee from the employ of a Subsidiary to the employ of the Company or another Subsidiary will be deemed to be a Termination of Employment of Grantee.

Nothing contained in this Agreement (i) obligates the Company or a Subsidiary to continue to employ Grantee in any capacity whatsoever or (ii) prohibits or restricts the Company or a Subsidiary from terminating the employment of Grantee at any time or for any reason whatsoever. In the event of a Termination of Employment of Grantee, Grantee will have only the rights set forth in this Agreement with respect to the Award Shares.

If at any time that any of the Target Shares have not vested or any of the Overperformance Shares are still outstanding the Company declares or pays any ordinary cash dividend, any non-cash dividend of securities or other property or rights to acquire securities or other property, any liquidating dividend of cash or property, or any stock dividend or there occurs any stock split or other change in the character or amount of any of the outstanding securities of the Company, then in such event: (i) any and all cash and new, substituted, or additional securities or other property relating or attributable to those Target Shares immediately and automatically will become subject to this Agreement, will be delivered to the Transfer Agent or to an independent escrow agent selected by the Company to be held by the Transfer Agent or such escrow agent pursuant to the terms of this Agreement, and will have the same status with respect to vesting and transfer as the unvested Award Shares upon which such dividend was paid or with respect to which such new, substituted, or additional securities or other property was distributed and (ii) a dividend equivalent dollar amount equal to the number of Overperformance Shares credited to Grantee’s Overperformance Share account pursuant to this Agreement as of the dividend record date multiplied by the dollar amount of any and all cash and new, substituted, or additional securities or other property relating or attributable to such Overperformance Shares will be credited to Grantee’s account, with any such amounts so credited subject to the same terms and conditions, including the timing of vesting and settlement, applicable to the underlying Overperformance Shares to which the dividend or dividend equivalents relate.

No interest will accrue on any cash or cash equivalents received by the Transfer Agent or such escrow agent or credited to Grantee’s account pursuant to the first sentence of this Section 6.

Grantee represents and warrants to the Company that Grantee has full legal power, authority, and capacity to execute and deliver this Agreement and to perform Grantee’s obligations under this Agreement; and this Agreement is a valid and binding obligation of Grantee, enforceable in accordance with its terms, except that the enforcement of this Agreement may be subject to bankruptcy, insolvency, reorganization, moratorium, or other similar laws now or hereafter in effect relating to creditors’ rights generally and to general principles of equity (regardless of whether such enforcement is considered in a proceeding in equity or at law).

The Company represents and warrants to Grantee as follows:

None of the Award Shares that have not vested in Grantee pursuant to Section 2 (and no beneficial interest in any of such Award Shares) may be sold, transferred, assigned, pledged, encumbered, or otherwise disposed of in any way by anyone (including a transfer by operation of law); and any attempt by anyone to make any such sale, transfer, assignment, pledge, encumbrance, or other disposition will be null and void and of no effect.

The Company and Grantee acknowledge that the Company’s remedy at law for any breach or violation or attempted breach or violation of the provisions of Section 9 will be inadequate and that, in the event of any such breach or violation or attempted breach or violation, the Company will be entitled to injunctive relief in addition to any other remedy, at law or in equity, to which the Company may be entitled.

Neither the Company nor the Transfer Agent will be required to transfer on the stock records of the Company maintained by either of them any Award Shares which have been sold, transferred, assigned, pledged, encumbered, or otherwise disposed of by anyone in violation of any of the provisions of this Agreement or to treat as the owner of such Award Shares or accord the right to vote or receive dividends to any purported transferee or pledgee to whom such Award Shares have been sold, transferred, assigned, pledged, encumbered, or otherwise disposed of in violation of any of the provisions of this Agreement.

Grantee has the right to make an election pursuant to Treasury Regulation § 1.83-2 with respect to the Target Shares granted on the Award Date and, if Grantee makes such election, promptly will furnish to the Company a copy of the form of election Grantee has filed with the Internal Revenue Service for such purpose and evidence that such an election has been made in a timely manner.

Grantee will have the right to vote with respect to all of the Target Shares granted on the Award Date, whether or not such Target Shares are vested in Grantee as of the record date. Except as otherwise provided in this Agreement, Grantee will have all of the rights of a stockholder of the Company with respect to all of the Target Shares granted on the Award Date which are outstanding, whether or not such Target Shares are vested in Grantee at such time. The Overperformance Shares subject to this Award do not entitle Grantee to any rights of a holder of Common Stock. Grantee will not have any of the rights of a stockholder of the Company in connection with the grant of Overperformance Shares subject to this Agreement unless and until such shares of Common Stock are issued to Grantee upon settlement of the Overperformance Shares as provided in Section 3(b)

The relevant provisions of the Plan relating to Restricted Stock Awards, with respect to the Target Shares, and Performance Unit Awards, with respect to the Overperformance Shares, and the authority of the Board under the Plan will be applicable to this Agreement to the extent that this Agreement does not otherwise expressly address the subject matter of such provisions.

Each such notice, request, consent, and other communication shall be deemed to have been given upon receipt thereof as set forth above or, if sooner, three (3) business days after deposit as described above. An address for purposes of this Section 16(b) may be changed by giving written notice of such change in the manner provided in this Section 16(b) for giving notice. Unless and until such written notice is received, the addresses referred to in this Section 16(b) shall be deemed to continue in effect for all purposes of this Agreement.

For example, if the Company undergoes a Change in Control that is a Corporate Transaction with a Transaction Stock Price of $72.50 per share of Common Stock, Tranche 1 has met its Stock Price Threshold and will have satisfied its performance condition, and one-half of Tranche 2 will have satisfied its performance condition based on linear interpolation. The Award Shares will continue to be subject to service-based vesting, subject to the following paragraph.

In addition, upon Grantee’s Eligible Termination after the occurrence of a Change in Control that is a Corporate Transaction under this Section 17(b), all service-based vesting of Award Shares in Tranches that have met their performance vesting conditions pursuant to Section 17(b)(i) will be accelerated and will be considered to have met all service-based vesting conditions.

The payments and benefits provided pursuant to this Agreement are intended to be exempt from Section 409A of the Code, and to the maximum extent permitted this Agreement will be interpreted and administered in accordance with this intent. If any amount is payable under this Agreement upon a Termination of Employment, a Termination of Employment will be deemed to have occurred only at such time as Grantee has experienced a “separation from service” as defined in Section 409A of the Code. Each amount to be paid or benefit to be provided under this Agreement shall be construed as a separate and distinct payment for purposes of Section 409A of the Code.

[Signature page follows.]

IN WITNESS WHEREOF, the Company and Grantee have executed this Performance-Based Restricted Stock Award Agreement on the dates set forth below, effective on the Award Date.