State notification register
Missouri data breach notification law: without unreasonable delay.
Missouri's breach-notification obligations are set by Mo. Rev. Stat. 407.1500. This page summarises the deadline to notify affected residents, the attorney general notification threshold, whether a private right of action exists, and the penalties for late or missing notification. Every provision is cited to its source statute and was verified in June 2026.
Individual deadline
No fixed day
Without unreasonable delay
AG notification
1,000
More than 1,000 Missouri consumers
Private action
No
AG has exclusive enforcement authority
Statute
MO
Mo. Rev. Stat. 407.1500
Section MO.1
What the statute requires
Under Mo. Rev. Stat. 407.1500, a business that owns or licenses computerized personal information of Missouri residents must notify affected individuals without unreasonable delay.
Attorney general or state-agency notification is more than 1,000 missouri consumers. Where required, the timeline is: without unreasonable delay.
Section MO.2
What triggers notification
Like most US state statutes, notification is triggered by the unauthorized acquisition of unencrypted, unredacted computerized personal information that compromises its security, confidentiality, or integrity. Two concepts recur across the states and apply here.
Encryption safe harbor
Personal information that was encrypted, and where the encryption key was not also acquired, generally does not trigger notification. A stolen device with full-disk encryption is typically a non-event; an unencrypted record, or an encrypted record where the key was exposed alongside it, is a reportable breach.
Who must be notified
- [1] Affected Missouri residents: without unreasonable delay
- [2] Attorney general / state agency: more than 1,000 missouri consumers
- [3] Consumer reporting agencies where the breach is large-scale
Section MO.3
Penalties and enforcement
Up to $150,000 per breach (or series) for willful and knowing violations.
Private right of action: No. AG has exclusive enforcement authority.
Primary source:Missouri statute Mo. Rev. Stat. 407.1500; verified June 2026 against state statutory summaries and the underlying statute text.
Section MO.4
How this compares to the strictest states
The strictest US deadlines are 30 days (California, Florida, Washington, Colorado, Maine, New York, New Jersey). The majority of states use a qualitative "without unreasonable delay" standard with no fixed day cap. Here is where Missouri sits.
Missouri does not set a numeric deadline. It uses a "without unreasonable delay" standard, which regulators interpret as days to weeks, not months. Organizations operating across multiple states should default to the strictest applicable clock, which can be as short as 30 days in states such as California, Colorado, Florida.
Cross-references
Index / All 50 states + DC
→The full register: deadline and AG threshold for every state.
Schedule 09 / Notification laws
→Global frameworks and the cost of notification.
01 / Breach cost calculator
→Estimate your Missouri breach exposure, including notification cost.
Regulation / GDPR
→The 72-hour clock and 4%-of-revenue fine framework.
Cost / Notification
→Why notification is roughly 6% of total breach cost.
Schedule F / Reference Q&A
Frequently Asked Questions
Primary source:Missouri data breach notification statute (Mo. Rev. Stat. 407.1500). Provisions verified June 2026 against state statutory summaries (Recording Law US data-privacy series, 2026 edition), the IAPP US State Data Breach Notification Chart, Foley & Lardner's chart, and the underlying statute text.