What is a materially significant cyber incident?

A materially significant cyber incident is one that meets the legal definition of materiality for SEC Item 1.05 disclosure, or the equivalent threshold for NIS2 significant incidents, DORA major ICT incidents, or CIRCIA covered cyber incidents. The determination triggers the disclosure clock.

Is materiality the same across regulatory regimes?

No. SEC uses the reasonable-investor materiality standard. NIS2 uses significant incident criteria specific to essential and important entities. DORA uses major ICT incident criteria specific to financial entities. CIRCIA uses covered cyber incident criteria specific to critical infrastructure. They overlap but are not identical.

Who determines materiality?

The reporting company determines materiality, typically with input from the CFO, CISO, General Counsel, outside counsel, and the disclosure committee or board. The determination process should be documented and consistent.

Can a single incident be material under multiple regimes?

Yes, often. A major ransomware incident at a U.S.-EU multinational financial entity may simultaneously trigger SEC Item 1.05 (public disclosure), DORA Article 19 (financial regulator), NIS2 Article 23 (national CSIRT), CIRCIA (CISA), GDPR Article 33 (EU DPAs), and state breach notification (multiple state attorneys general).

How is the materiality clock measured?

Under SEC Item 1.05, four business days from the materiality determination, not from the incident or detection. Under NIS2 it is 24 hours from awareness for the early warning. Under DORA it is 4 hours from classification as a major incident. Under CIRCIA it is 72 hours from reasonable belief.

Materially Significant Cyber Incident

A materially significant cyber incident is one that meets the legal definition of materiality for SEC disclosure under Item 1.05 of Form 8-K, or the equivalent regulatory threshold for other regimes (NIS2 "significant incident," DORA "major ICT incident," CIRCIA "covered cyber incident"). The materiality determination is the trigger that starts the disclosure clock for U.S. public companies and the equivalent reporting clocks elsewhere.

Source: SEC Release No. 33-11216, NIS2 Article 23, DORA Article 19, CIRCIA NPRM (89 FR 23644).

Cross-Regime Comparison

Regime	Threshold	Clock
SEC Item 1.05	Material (reasonable investor standard)	4 business days from determination
NIS2	Significant (operational disruption or substantial impact)	24h early warning, 72h notification, 1 month final
DORA	Major ICT incident	4h initial, 72h intermediate, 1 month final
CIRCIA	Covered cyber incident	72h from reasonable belief

Making the Determination

The materiality determination is qualitative and contextual. Consider financial impact, operational disruption, regulatory and litigation exposure, reputational harm, competitive consequences, and effects on specific business segments. Document the inputs, the analysis, and the timing of the determination, because the determination process itself can be subject to enforcement scrutiny.

Common Pitfalls

Delaying the determination to delay the clock (the SEC explicitly rejected this approach)
Using a quantitative threshold (no defined dollar amount triggers Item 1.05)
Treating "material" as a one-time decision when ongoing developments may change the analysis
Not documenting the materiality determination process
Treating SEC materiality and other regulatory thresholds (NIS2, DORA, CIRCIA) as identical

Track materiality determinations defensibly

IR-OS captures the materiality determination process and produces a defensible record showing exactly when and how the threshold was crossed.

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Materially Significant Cyber Incident

Cross-Regime Comparison

Making the Determination

Common Pitfalls

Related Terms

Track materiality determinations defensibly