ADTRAN Holdings, Inc. 8-K

What Happened
ADTRAN Holdings, Inc. announced on January 21, 2026 that it released certain preliminary financial results for the fiscal quarter and year ended December 31, 2025 and filed an 8-K (Item 2.02) reporting those results. The company also published an ad hoc announcement in Germany on the same date under Article 17 of the EU Market Abuse Regulation (MAR) to disclose the preliminary quarterly results to Frankfurt Stock Exchange investors. The 8-K includes a press release (Exhibit 99.1) and an English translation of the MAR ad hoc notification (Exhibit 99.2).

Key Details

• Date of disclosure: January 21, 2026.
• Period covered: fiscal quarter and fiscal year ended December 31, 2025 (preliminary results disclosed).
• Filings: 8-K reporting preliminary results (Item 2.02) and MAR ad hoc announcement (Item 7.01); Exhibits 99.1 (press release) and 99.2 (ad hoc notification, English).
• Report signed by Timothy Santo, Senior VP of Finance and CFO.

Why It Matters
Preliminary quarterly and year-end results can affect investor expectations for earnings, revenue and future guidance; the simultaneous MAR ad hoc notice indicates the information may be material for European investors and could reflect a meaningful deviation from prior guidance or analyst consensus. Retail investors should read the attached press release and ad hoc notice for the specific figures and monitor forthcoming SEC filings (e.g., Form 10-K or a full earnings release) for audited results and management commentary before making investment decisions.