ACI WORLDWIDE, INC.

We provide the information below to reconcile to GAAP thosenon-GAAP financial metrics used by management to measure performance and those financial metrics used that are eithernon-GAAP financial metrics or reflect approved adjustments. Thenon-GAAP measures exclude significant transaction-related expenses, as well as other significantnon-cash expenses such as depreciation, amortization, and stock-based compensation, that we believe are helpful in understanding our past financial performance and our future results. The presentation of thesenon-GAAP financial measures should be considered in addition to our GAAP results and are not intended to be considered in isolation or as a substitute for the financial information prepared and presented in accordance with GAAP. Management generally compensates for limitations in the use ofnon-GAAP financial measures by relying on comparable GAAP financial measures and providing investors with a reconciliation ofnon-GAAP financial measures only in addition to and in conjunction with results presented in accordance with GAAP. We believe that thesenon-GAAP financial measures reflect an additional way to view aspects of our operations that, when viewed with our GAAP results, provide a more complete understanding of factors and trends affecting our business.

Revenue Net of Interchange

Revenue Net of Interchange is anon-GAAP financial measure defined as revenue net of pass-through interchange revenue. Revenue Net of Interchange should be considered in addition to, rather than as a substitute for, revenue. For purposes of calculations under our 2024 short-term incentive program awards and our 2024 PSU awards, we further adjusted Revenue Net of Interchange (including for purposes of calculating Net Adjusted EBITDA Margin) to be based on our 2024 budgeted foreign exchange rate rather than our actual foreign exchange rates. For purposes of calculations under our 2025 short-term incentive program awards under our 2025 PSU awards, we further adjusted Revenue Net of Interchange (including for purposes of calculating Net Adjusted EBITDA Margin) to be based on 2025 budgeted foreign exchange rate rather than our actual foreign exchange rates. The following is a reconciliation of Revenue Net of Interchange to revenue for the years ended December 31, 2025 and 2024:

Adjusted EBITDA and Net Adjusted EBITDA Margin

Adjusted EBITDA is anon-GAAP financial measure defined as net income plus income tax expense (benefit), net interest income (expense), net other income (expense), depreciation, amortization and stock-based compensation, as well as significant transaction-related expenses. Adjusted EBITDA should be considered in addition to, rather than as a substitute for, net income. Net Adjusted EBITDA Margin is anon-GAAP financial measure defined as Adjusted EBITDA divided by Revenue Net of Interchange. For purposes of calculations under our 2024 short-term incentive program awards and our 2024 PSU awards, we further adjusted Adjusted EBITDA (including for purposes of calculating Net Adjusted EBITDA Margin) to be based on our 2024 budgeted foreign exchange rate rather than our actual foreign exchange rates. For purposes of calculations under our 2025 short-term incentive program awards and our 2025 PSU awards, we further adjusted Adjusted EBITDA (including for purposes of calculating Net Adjusted EBITDA Margin) to be based on our 2025 budgeted foreign exchange rate rather than our actual foreign exchange rates.

2026 PROXY STATEMENT A-1

The following is a reconciliation of Adjusted EBITDA to net income for the years ended December 31, 2025 and 2024:

The undersigned hereby appoints Craig Maki and Sara Arrasmith (the “Named Proxies”), and each or either of them, as the true and lawful attorneys of the undersigned, with full power of substitution and revocation, and authorizes them, and each of them, to vote all the shares of capital stock of ACI Worldwide, Inc. which the undersigned is entitled to vote at said meeting and any adjournment thereof upon the matters specified and upon such other matters as may be properly brought before the meeting or any adjournment thereof, conferring authority upon such true and lawful attorneys to vote in their discretion on such other matters as may properly come before the meeting and revoking any proxy heretofore given.

THE SHARES REPRESENTED BY THIS PROXY WILL BE VOTED AS DIRECTED OR, IF NO DIRECTION IS GIVEN, SHARES WILL BE VOTED IDENTICAL TO THE BOARD OF DIRECTORS’ RECOMMENDATION. This proxy, when properly executed, will be voted in the manner directed herein. In their discretion, the Named Proxies are authorized to vote upon such other matters that may properly come before the meeting or any adjournment or postponement thereof.

You are encouraged to specify your choice by marking the appropriate box (SEE REVERSE SIDE) but you need not mark any box if you wish to vote in accordance with the Board of Directors’ recommendation. The Named Proxies cannot vote your shares unless you sign (on the reverse side) and return this card. PLEASE BE SURE TO SIGN AND DATE THIS PROXY CARD AND MARK ON THE REVERSE SIDE Copyright © 2026 BetaNXT, Inc. or its affiliates. All Rights Reserved

ACI Worldwide, Inc. Annual Meeting of Stockholders

Please make your marks like this:

THE BOARD OF DIRECTORS RECOMMENDS A VOTE:

FOR ALL NOMINEES FOR DIRECTOR ON PROPOSAL 1, AND FOR PROPOSALS 2 AND 3

You must register to attend the meeting online and/or participate at www.proxydocs.com/ACIW

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