Johnson Fistel Investigates ADTRAN Holdings, Inc. (ADTN) for Potential Securities Law Violations

Johnson Fistel, PLLP is investigating ADTRAN Holdings, Inc. (NASDAQ: ADTN) on behalf of investors who suffered losses and whether those losses may be recoverable under federal securities laws. On July 22, 2026, ADTRAN announced preliminary second-quarter 2026 results indicating that non-GAAP operating margins would be significantly below its previously issued guidance. The Company attributed the shortfall to a project delay involving a single customer and higher-than-expected component and freight costs, which negatively impacted profitability. Following the announcement, ADTRAN's stock declined sharply in early morning trading. Johnson Fistel is investigating whether ADTRAN failed to timely disclose customer project delays and increasing cost pressures that materially affected its second-quarter financial performance. The investigation focuses on whether management knew, or should have known, that these adverse conditions had materially reduced revenue and operating margins, making the Company's previously issued guidance unattainable, yet failed to timely disclose this information to investors. If you purchased ADTRAN securities and suffered losses, or possess information that may assist this investigation, please contact Johnson Fistel to discuss your legal rights.