Since the SEC's final cybersecurity rules took effect in December 2023, public companies filed more than 85 material incident disclosures under Item 1.05 of Form 8-K. The regulatory clock now runs four business days from materiality determination to public filing. What emerged in year one is not a flood, but a pattern: healthcare, financial services, and technology firms account for roughly 70% of reported events, and the median disclosure runs under 300 words.

The filings themselves split into three categories. Ransomware events, often coded as "unauthorized access to certain systems," dominate the healthcare sector. Data exfiltration tied to third-party vendors concentrates in financials. Software supply chain compromises appear in technology and industrials, typically disclosed after the vendor announces its own breach. Most companies describe immediate containment, engagement of external forensic firms, and notification of law enforcement. Few quantify financial impact at the time of filing, citing ongoing investigation. The SEC permits delay only when the U.S. Attorney General certifies substantial national security or public safety risk—invoked zero times in the public record to date.

For allocators, the disclosure quality varies enough to matter. Stronger filings name the attack vector, specify affected data types, and provide a timeline from detection to containment. Weaker filings rely on boilerplate: "We take cybersecurity seriously" and "We maintain robust controls." The language gap correlates with subsequent stock price volatility. Companies disclosing within 48 hours of materiality determination saw median single-day declines of 1.2%. Those waiting until day four saw 3.1%. The market prices delay as control failure.

The rules also introduced annual cybersecurity governance disclosures on Form 10-K, effective for fiscal years ending on or after December 15, 2023. Public companies must now describe board oversight, management's role, and processes for assessing and managing cyber risk. Early 10-K filings reveal wide variance: some boards receive quarterly briefings from CISOs with quantified risk metrics, others describe "periodic updates as needed." The discrepancy suggests boards at smaller-cap firms treat cyber as compliance theater rather than enterprise risk. Family offices holding concentrated positions in sub-$5B market cap names should request the board's actual cyber briefing deck during diligence.

Operators should track three near-term developments. First, the SEC's Division of Enforcement opened at least six investigations into delayed or incomplete 8-K filings in year one, per public enforcement data. Expect settlements by mid-2025 that clarify what "material" means in practice. Second, insurance carriers now request copies of prior 8-K cyber filings during D&O renewal underwriting, tightening the link between disclosure quality and premium cost. Third, plaintiff firms filed securities class actions tied to 12 of the year-one cyber disclosures, alleging the company knew or should have known of control deficiencies earlier. The litigation risk shifts how general counsel time the materiality call.

The pattern that matters most is this: median time from initial compromise to company detection remains 21 days across disclosed incidents. The SEC's four-day disclosure window compresses response time but does nothing to shorten dwell time. Boards that treat the 8-K filing as the risk are missing the operational gap. The next wave of material incidents will come from AI tooling deployed without logging, third-party SaaS integrations approved by business units, and legacy OT systems never designed for internet exposure. None of those risks appear in current 10-K governance narratives, which means the market has not priced them yet.