Material Event (Form 8-K)

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.

In connection with the Merger, the Company and Parent submitted a joint voluntary notice under Section 721 of the Defense Production Act of 1950, as amended, with the Committee on Foreign Investment in the United States ("CFIUS").

On May 7, 2026, the Company and Parent received written notice from CFIUS that constitutes CFIUS Clearance (as defined in the Merger Agreement).

All required regulatory approvals to complete the Merger have now been received.