Condensed Consolidated Financial Statements (Policies)	9 Months Ended
Sep. 30, 2025
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Consolidation	The unaudited condensed consolidated financial statements include the accounts of ACI Worldwide, Inc. and its wholly-owned subsidiaries (collectively, the “Company”). All intercompany balances and transactions have been eliminated. The condensed consolidated financial statements as of September 30, 2025, and for the three and nine months ended September 30, 2025 and 2024, are unaudited and reflect all adjustments of a normal recurring nature, which are, in the opinion of management, necessary for a fair presentation, in all material respects, of the financial position and operating results for the interim periods. The condensed consolidated balance sheet as of December 31, 2024, is derived from the audited financial statements. The condensed consolidated financial statements contained herein should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2024, filed on February 27, 2025. Results for the three and nine months ended September 30, 2025, are not necessarily indicative of results that may be attained in the future.
Use of Estimates	The preparation of condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make judgments, estimates, and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions are affected by management’s application of accounting policies, as well as uncertainty in the current economic environment. Actual results could differ from those estimates.
Settlement Assets and Liabilities	Settlement Assets and Liabilities Individuals and businesses settle their obligations to the Company’s various Biller clients using credit or debit cards or via automated clearing house (“ACH”) payments. The Company creates a receivable for the amount due from the credit or debit card processor and an offsetting payable to the client. Upon confirmation that the funds have been received, the Company settles the obligation to the client. Due to timing, in some instances, the Company may (1) receive the funds into bank accounts controlled by and in the Company’s name that are not disbursed to its clients by the end of the day, resulting in a settlement deposit on the Company’s books and (2) disburse funds to its clients in advance of receiving funds from the credit or debit card processor, resulting in a net settlement receivable position.
Off Balance Sheet Settlement Accounts	Off Balance Sheet Settlement Accounts The Company also enters into agreements with certain Biller clients to process payment funds on their behalf. When an ACH or automated teller machine network payment transaction is processed, a transaction is initiated to withdraw funds from the designated source account and deposit them into a settlement account, which is a trust account maintained for the benefit of the Company’s clients. A simultaneous transaction is initiated to transfer funds from the settlement account to the intended destination account. These “back to back” transactions are designed to settle at the same time, usually overnight, such that the Company receives the funds from the source at the same time as it sends the funds to their destination. However, due to the transactions being with various financial institutions there may be timing differences that result in float balances. These funds are maintained in accounts for the benefit of the client which is separate from the Company’s corporate assets. As the Company does not take ownership of the funds, these settlement accounts are not included in the Company’s balance sheet. The Company is entitled to interest earned on the fund balances. The collection of interest on these settlement accounts is considered in the Company’s determination of its fee structure for clients and represents a portion of the payment for services performed by the Company.
Fair Value	Fair Value The fair value of the Company’s Credit Agreement approximates the carrying value due to the floating interest rate (Level 2 of the fair value hierarchy). The Company measured the fair value of its Senior Notes based on Level 2 inputs, which include quoted market prices and interest rate spreads of similar securities.
Goodwill	Goodwill In accordance with the Accounting Standards Codification ("ASC") 350, Intangibles – Goodwill and Other, the Company assesses goodwill for impairment annually during the fourth quarter of its fiscal year using October 1 balances or when there is evidence that events or changes in circumstances indicate that the carrying amount of the asset may not be recovered. The Company evaluates goodwill at the reporting unit level, and as discussed in Note 9, Segment Information, in 2025 it realigned Banks and Merchants under a single general manager leading Payment Software. This change also resulted in a change in reporting units - combining Banks and Merchants into Payment Software, while maintaining Biller. As of September 30, 2025, the Company's goodwill balance of $1.2 billion was allocated $809.0 million to Payment Software and $417.0 million to Biller. Recoverability of goodwill is measured using a discounted cash flow model incorporating discount rates commensurate with the risks involved. Use of a discounted cash flow model is common practice in impairment testing in the absence of available transactional market evidence to determine the fair value. The calculated fair value was substantially in excess of the current carrying value for all reporting units based upon the October 1, 2024, annual impairment test and there have been no indications of impairment in the subsequent periods.
Equity Method Investment	Equity Method Investment In July 2019, the Company invested $18.3 million for a 30% non-controlling financial interest in a payment technology and services company in India. The Company accounted for this investment using the equity method in accordance with ASC 323, Investments - Equity Method and Joint Ventures, and recorded its share of earnings and losses in the investment on a one-quarter lag basis. The Company had recorded an investment of $18.6 million, included in other noncurrent assets in the condensed consolidated balance sheet as of December 31, 2024. In March 2025, the Company sold its 30% interest for $46.0 million. The Company recognized a gain on the sale of $25.9 million, which is recorded in other, net in the condensed consolidated statements of operations.
Recently Issued Accounting Standards Not Yet Effective and Recently Adopted Accounting Pronouncements	Recently Issued Accounting Standards Not Yet Effective In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The amendments in this update will require entities to provide disaggregated disclosures of specific expense categories underlying certain income statement expense line items on an annual and interim basis. ASU 2024-03 is effective for annual periods beginning after December 15, 2026, and early application is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact that the adoption of ASU 2024-03 will have on its financial statement footnote disclosures. In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326), to simplify the estimation of expected credit losses for certain short-term receivables and contract assets arising from revenue transactions. The ASU introduces a practical expedient that allows entities to assume current economic conditions will persist through the reasonable and supportable forecast period for eligible assets. ASU 2025-05 is effective for annual periods beginning after December 15, 2025, with early adoption permitted. The Company does not expect the adoption of ASU 2025-05 to have a material impact on its condensed consolidated financial statements or related disclosures. In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. The amendments in this update modernize the accounting guidance for internal-use software by replacing the previous stage-based model with a principles-based framework. Under the new guidance, cost capitalization begins when (1) management has authorized and committed to funding the software project and (2) it is probable that the project will be completed and the software will be used for its intended purpose. The update also supersedes the existing rules for website development costs, incorporating them into the internal-use software framework. ASU 2025-06 is effective for annual periods beginning after December 15, 2027, and early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2025-06 will have on its condensed consolidated financial statements and related disclosures. Recently Adopted Accounting Pronouncements In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this update will require disclosure of more disaggregated information about a reporting entity's effective tax rate reconciliation and income taxes paid. ASU 2023-09 is effective for our annual period beginning after December 15, 2024. ASU 2023-09 is expected to impact our income tax disclosures beginning with the consolidated financial statements included in the annual report on Form 10-K for the fiscal year ended December 31, 2025, but is not expected to have an impact on the Company's financial position, results of operations or cash flows.

Condensed Consolidated Financial Statements (Policies)

9 Months Ended

Sep. 30, 2025

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The unaudited condensed consolidated financial statements include the accounts of ACI Worldwide, Inc. and its wholly-owned subsidiaries (collectively, the “Company”). All intercompany balances and transactions have been eliminated. The condensed consolidated financial statements as of September 30, 2025, and for the three and nine months ended September 30, 2025 and 2024, are unaudited and reflect all adjustments of a normal recurring nature, which are, in the opinion of management, necessary for a fair presentation, in all material respects, of the financial position and operating results for the interim periods. The condensed consolidated balance sheet as of December 31, 2024, is derived from the audited financial statements.

The condensed consolidated financial statements contained herein should be read in conjunction with the consolidated financial statements and notes thereto contained in the Company’s annual report on Form 10-K for the fiscal year ended December 31, 2024, filed on February 27, 2025. Results for the three and nine months ended September 30, 2025, are not necessarily indicative of results that may be attained in the future.

Use of Estimates

The preparation of condensed consolidated financial statements in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”) requires management to make judgments, estimates, and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. These estimates and assumptions are affected by management’s application of accounting policies, as well as uncertainty in the current economic environment. Actual results could differ from those estimates.

Settlement Assets and Liabilities

Individuals and businesses settle their obligations to the Company’s various Biller clients using credit or debit cards or via automated clearing house (“ACH”) payments. The Company creates a receivable for the amount due from the credit or debit card processor and an offsetting payable to the client. Upon confirmation that the funds have been received, the Company settles the obligation to the client. Due to timing, in some instances, the Company may (1) receive the funds into bank accounts controlled by and in the Company’s name that are not disbursed to its clients by the end of the day, resulting in a settlement deposit on the Company’s books and (2) disburse funds to its clients in advance of receiving funds from the credit or debit card processor, resulting in a net settlement receivable position.

Off Balance Sheet Settlement Accounts

The Company also enters into agreements with certain Biller clients to process payment funds on their behalf. When an ACH or automated teller machine network payment transaction is processed, a transaction is initiated to withdraw funds from the designated source account and deposit them into a settlement account, which is a trust account maintained for the benefit of the Company’s clients. A simultaneous transaction is initiated to transfer funds from the settlement account to the intended destination account. These “back to back” transactions are designed to settle at the same time, usually overnight, such that the Company receives the funds from the source at the same time as it sends the funds to their destination. However, due to the transactions being with various financial institutions there may be timing differences that result in float balances. These funds are maintained in accounts for the benefit of the client which is separate from the Company’s corporate assets. As the Company does not take ownership of the funds, these settlement accounts are not included in the Company’s balance sheet. The Company is entitled to interest earned on the fund balances. The collection of interest on these settlement accounts is considered in the Company’s determination of its fee structure for clients and represents a portion of the payment for services performed by the Company.

Fair Value

The fair value of the Company’s Credit Agreement approximates the carrying value due to the floating interest rate (Level 2 of the fair value hierarchy). The Company measured the fair value of its Senior Notes based on Level 2 inputs, which include quoted market prices and interest rate spreads of similar securities.

Goodwill

In accordance with the Accounting Standards Codification ("ASC") 350, Intangibles – Goodwill and Other, the Company assesses goodwill for impairment annually during the fourth quarter of its fiscal year using October 1 balances or when there is evidence that events or changes in circumstances indicate that the carrying amount of the asset may not be recovered. The Company evaluates goodwill at the reporting unit level, and as discussed in Note 9, Segment Information, in 2025 it realigned Banks and Merchants under a single general manager leading Payment Software. This change also resulted in a change in reporting units - combining Banks and Merchants into Payment Software, while maintaining Biller. As of September 30, 2025, the Company's goodwill balance of $1.2 billion was allocated $809.0 million to Payment Software and $417.0 million to Biller.

Recoverability of goodwill is measured using a discounted cash flow model incorporating discount rates commensurate with the risks involved. Use of a discounted cash flow model is common practice in impairment testing in the absence of available transactional market evidence to determine the fair value. The calculated fair value was substantially in excess of the current carrying value for all reporting units based upon the October 1, 2024, annual impairment test and there have been no indications of impairment in the subsequent periods.

Equity Method Investment

In July 2019, the Company invested $18.3 million for a 30% non-controlling financial interest in a payment technology and services company in India. The Company accounted for this investment using the equity method in accordance with ASC 323, Investments - Equity Method and Joint Ventures, and recorded its share of earnings and losses in the investment on a one-quarter lag basis. The Company had recorded an investment of $18.6 million, included in other noncurrent assets in the condensed consolidated balance sheet as of December 31, 2024. In March 2025, the Company sold its 30% interest for $46.0 million. The Company recognized a gain on the sale of $25.9 million, which is recorded in other, net in the condensed consolidated statements of operations.

Recently Issued Accounting Standards Not Yet Effective and Recently Adopted Accounting Pronouncements

Recently Issued Accounting Standards Not Yet Effective

In November 2024, the FASB issued ASU 2024-03, Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statement Expenses. The amendments in this update will require entities to provide disaggregated disclosures of specific expense categories underlying certain income statement expense line items on an annual and interim basis. ASU 2024-03 is effective for annual periods beginning after December 15, 2026, and early application is permitted for annual financial statements that have not yet been issued or made available for issuance. The Company is currently assessing the impact that the adoption of ASU 2024-03 will have on its financial statement footnote disclosures.

In July 2025, the FASB issued ASU 2025-05, Financial Instruments—Credit Losses (Topic 326), to simplify the estimation of expected credit losses for certain short-term receivables and contract assets arising from revenue transactions. The ASU introduces a practical expedient that allows entities to assume current economic conditions will persist through the reasonable and supportable forecast period for eligible assets. ASU 2025-05 is effective for annual periods beginning after December 15, 2025, with early adoption permitted. The Company does not expect the adoption of ASU 2025-05 to have a material impact on its condensed consolidated financial statements or related disclosures.

In September 2025, the FASB issued ASU 2025-06, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. The amendments in this update modernize the accounting guidance for internal-use software by replacing the previous stage-based model with a principles-based framework. Under the new guidance, cost capitalization begins when (1) management has authorized and committed to funding the software project and (2) it is probable that the project will be completed and the software will be used for its intended purpose. The update also supersedes the existing rules for website development costs, incorporating them into the internal-use software framework. ASU 2025-06 is effective for annual periods beginning after December 15, 2027, and early adoption is permitted. The Company is currently evaluating the impact that the adoption of ASU 2025-06 will have on its condensed consolidated financial statements and related disclosures.

Recently Adopted Accounting Pronouncements

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, to enhance the transparency and decision usefulness of income tax disclosures. The amendments in this update will require disclosure of more disaggregated information about a reporting entity's effective tax rate reconciliation and income taxes paid. ASU 2023-09 is effective for our annual period beginning after December 15, 2024. ASU 2023-09 is expected to impact our income tax disclosures beginning with the consolidated financial statements included in the annual report on Form 10-K for the fiscal year ended December 31, 2025, but is not expected to have an impact on the Company's financial position, results of operations or cash flows.