Form 8-K Item 1.05 is the U.S. Securities and Exchange Commission disclosure item public companies use to report a material cybersecurity incident. If an incident is important enough that a reasonable investor would want to know about it, the company may need to file an 8-K describing the nature, scope, timing, and material impact of the event.
This matters because disclosure can be required before forensic analysis is finished. Security teams, legal counsel, and compliance staff must quickly decide whether the incident is material, preserve evidence, and prepare accurate public statements without overstating certainty. In practice, Item 1.05 often appears after intrusions involving stolen credentials, impersonation, ransomware, or other events that expose confidential data or disrupt operations. Good defenses include clear incident classification, strong logging, out-of-band verification for suspicious requests, and a documented disclosure workflow so that regulatory reporting keeps pace with the investigation.