8-K

CSG SYSTEMS INTERNATIONAL, INC.

Date: January 6, 2026

/s/ Rasmani Bhattacharya

Rasmani Bhattacharya

Chief Legal Officer

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of Earliest Event Reported): January 5, 2026

CSG SYSTEMS INTERNATIONAL, INC.

(Exact Name of Registrant as Specified in Its Charter)

Delaware

0-27512

47-0783182

(State or Other Jurisdiction

of Incorporation)

(Commission

File Number)

(IRS Employer

Identification No.)


169 Inverness Dr W, Ste 300, Englewood, CO				80112
(Address of Principal Executive Offices)				(Zip Code)

(303) 200-2000

(Registrant’s Telephone Number, Including Area Code)

Former Name or Former Address, If Changed Since Last Report: N/A

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐	Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐	Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐	Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐	Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading

Symbol(s)

Name of each exchange

on which registered

Common Stock, par value $0.01 per share

CSGS

The NASDAQ Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01

Other Events.

As previously disclosed, on October 29, 2025, CSG Systems International, Inc., a Delaware corporation (the “Company”), entered into an Agreement and Plan of Merger (the “Merger Agreement”), dated as October 29, 2025, with NEC Corporation, a company incorporated under the laws of Japan (“Parent”), and Canvas Transaction Company, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Merger Sub”), pursuant to which, on the terms and subject to the conditions set forth in the Merger Agreement, Merger Sub will merge with and into the Company (the “Merger”), with the Company continuing as the surviving corporation in the Merger and a wholly owned subsidiary of Parent.

Among other things, the completion of the Merger is conditioned upon the expiration or termination of the waiting period applicable to the Merger under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Waiting Period”). The HSR Waiting Period expired at 11:59 pm Eastern Time on January 5, 2026. The closing of the Merger remains subject to the receipt of other required regulatory approvals, adoption of the Merger Agreement by the holders of a majority of the Company’s outstanding common stock entitled to vote thereon, as well as other customary closing conditions.

Forward-Looking Statements

This Form 8-K contains “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Forward-looking statements include, but are not limited to, statements concerning the Company’s expectations, plans, intentions, strategies or prospects with respect to the proposed transaction. These statements are often identified by the use of words such as “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “hope,” “hopeful,” “likely,” “may,” “optimistic,” “possible,” “potential,” “preliminary,” “project,” “should,” “will,” “would” or the negative or plural of these words or similar expressions or variations. Forward-looking statements are made based upon management’s current expectations and beliefs and are not guarantees of future performance. Such forward-looking statements are subject to a number of risks, uncertainties, assumptions and other factors that could cause actual results and the timing of certain events to differ materially from future results expressed or implied by the forward-looking statements. These factors include, among others: (i) the ability of the parties to complete the proposed transaction on the anticipated terms and timing, or at all, (ii) the satisfaction or waiver of other conditions to the completion of the proposed transaction, including obtaining required shareholder and regulatory approvals; (iii) the risk that the Company’s stock price may fluctuate during the pendency of the proposed transaction and may decline if the proposed transaction is not completed; (iv) potential litigation relating to the proposed transaction that could be instituted against the Company or its directors, managers or officers, including the delay, expense or other effects of any outcomes related thereto; (v) the risk that disruptions from the proposed transaction will harm the Company’s business, including current plans and operations, including during the pendency of the proposed transaction; (vi) the ability of the Company to retain, motivate and hire key personnel; (vii) the diversion of management’s time and attention from ordinary course business operations to completion of the proposed transaction and integration matters; (viii) potential adverse reactions or changes to business relationships resulting from the announcement, pendency or completion of the proposed transaction; (ix) legislative, regulatory and economic developments; (x) potential business uncertainty, including changes to existing business relationships, during the pendency of the proposed transaction that could affect the Company’s financial performance; (xi) certain restrictions during the pendency of the proposed transaction that may impact the Company’s ability to pursue certain business opportunities or strategic transactions; (xii) unpredictability and severity of catastrophic events, including but not limited to acts of terrorism, outbreaks of war or hostilities or global pandemics, as well as management’s response to any of the aforementioned factors; (xiii) the possibility that the proposed transaction may be more expensive to complete than anticipated, including as a result of unexpected factors or events; (xiv) unexpected costs, liabilities or delays associated with the transaction; (xv) the response of competitors to the transaction; (xvi) the occurrence of any event, change or other circumstance that could give rise to the termination of the proposed transaction, including in circumstances requiring the Company to pay a termination fee; (xvii) the ability to realize the anticipated benefits of the proposed transaction, including the expected synergies and cost saving; (xviii) the possibility that competing or superior acquisition proposals for the Company will be made; and (xix) other risks set forth under the heading “Risk Factors,” of the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 and in the Company’s subsequent filings with the Securities and Exchange Commission. You should not rely upon forward-looking statements as predictions of future events. Furthermore, such forward-looking statements speak only as of the date of this report. Actual results could differ materially from the results described in or implied by such forward-looking statements. Forward-looking statements speak only as of the date hereof, and, except as required by law, the Company undertakes no obligation to update or revise these forward-looking statements.

Additional Information and Where to Find It

This communication does not constitute an offer to buy or sell or the solicitation of an offer to buy or sell any securities or a solicitation of any vote or approval. This communication relates to a proposed acquisition of CSG Systems International, Inc. by NEC Corporation. In connection with this proposed acquisition, CSG Systems International, Inc. may file one or more proxy statements or other documents with the SEC. This communication is not a substitute for any proxy statement or other document that CSG Systems International, Inc. has filed or may file with the SEC in connection with the proposed transaction. INVESTORS AND SECURITY HOLDERS OF CSG SYSTEMS INTERNATIONAL, INC. ARE URGED TO READ THE PROXY STATEMENT AND OTHER DOCUMENTS THAT HAVE BEEN (OR MAY BE) FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY CONTAIN IMPORTANT INFORMATION. The definitive proxy statement has been mailed to stockholders of CSG Systems International, Inc. Investors and security holders may obtain free copies of these documents and other documents filed with the SEC by CSG Systems International, Inc. through the website maintained by the SEC at http://www.sec.gov. Copies of the documents filed with the SEC by CSG Systems International, Inc. will be available free of charge on CSG Systems International, Inc.’s internet website at https://ir.csgi.com/investor-home/default.aspx or upon written request to: CSG Systems International, Inc., Investor Relations, 169 Inverness Dr W, Suite 300, Englewood, CO 80112 or by email to john.rea@csgi.com.

Participants in Solicitation

CSG Systems International, Inc., its directors and certain of its executive officers and employees may be deemed to be participants in the solicitation of proxies in connection with the proposed transaction. Information about the directors and executive officers of CSG Systems International, Inc. is set forth in the proxy statement filed with the SEC on December 16, 2025 and its proxy statement for its 2025 annual meeting of stockholders, which was filed with the SEC on April 1, 2025. Additional information regarding the participants in the proxy solicitation and a description of their direct and indirect interests, by security holdings or otherwise, is contained in the proxy statement relating to the proposed transaction and other relevant materials filed with the SEC. These documents can be obtained free of charge from the sources indicated above.

CSG Systems International, Inc.

Investor Relations

169 Inverness Dr W, Suite 300, Englewood, CO 80112

https://ir.csgi.com/investor-home/default.aspx

john.rea@csgi.com

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

SEC Form 8-K filed by CSG Systems International Inc.