The 4-business-day 8-K clock.
Item 1.05 of Form 8-K requires disclosure within four business days — but the clock starts when the registrant determines the incident is material, NOT when the incident is discovered. This distinction is load-bearing. Discovery can precede determination by hours, days, or weeks, and the determination itself is the registrant's call (made without unreasonable delay). The four-business-day count begins the day after that determination.
Source: Form 8-K, Item 1.05, as adopted in the July 26, 2023 Final Rule. The determination-start (rather than discovery-start) framing is the SEC's; the rule and the rule release describe it directly.
