Periodic review is the scheduled re-examination of existing customers, typically more often for higher-risk customers and less often for lower-risk ones. Perpetual KYB (also called perpetual or event-driven KYC) is the approach of monitoring business customers continuously and triggering a review when something relevant changes, such as a new officer, a status change at the registry or a screening hit. Most programs use some mix of the two.
Why it matters in KYB review
Onboarding is a snapshot. The obligation continues: US bank AML programs must include ongoing monitoring that, on a risk basis, maintains and updates customer information, including beneficial ownership of legal entity customers (31 CFR 1020.210). The rule describes the outcome, not the schedule, which leaves institutions to decide how and when to look again.
FinCEN's February 2026 exceptive relief order (FIN-2026-R001) points the same way for beneficial ownership. Beyond the first account, covered institutions re-identify and re-verify beneficial owners when facts "reasonably call into question the reliability" of what they hold, or as their risk-based ongoing due diligence requires. An event-driven design is a natural fit for the first of those conditions.
Periodic versus perpetual
| Periodic review | Perpetual KYB | |
|---|---|---|
| What starts a review | A date set by risk tier | A detected change or alert |
| Strength | Predictable coverage of every customer | Catches changes close to when they happen |
| Weakness | Changes can sit unnoticed until the next date | Depends on data feeds; silent changes are missed |
| Workload | Lumpy, driven by the calendar | Spiky, driven by events |
What an analyst checks
Each triggered or scheduled case is a KYB refresh: status, ownership and control, activity against the declared profile, fresh screening, and an updated risk rating. For event-driven cases, the analyst also records the trigger and whether it turned out to be material.
Common pitfalls
- Alert floods. Registry feeds generate many harmless events, such as address updates or annual filings. Without triage rules, perpetual KYB turns into a new manual review queue.
- Blind spots. Some changes never reach a public registry. A private share sale can move ownership without any filing. Scheduled reviews and customer attestations cover that gap.
- Backlogged schedules. A schedule nobody keeps up with gives neither predictable coverage nor early warning. Track the overdue count as a queue metric.
- No link back to onboarding. A review that does not compare against the original file cannot say what changed.
Related terms
KYB refresh, ultimate beneficial owner, evidence packet, four-eyes review.
How Sweat AI fits
Sweat AI's analysts, working with AI tools, can take both scheduled and event-driven review cases off your queue and return each with what changed, the evidence and a recommendation, while the decision stays with your team. See KYB review.
Questions
Does perpetual KYB replace periodic review?
Usually it supplements it. Event triggers catch changes early, and a scheduled review still covers customers whose risk drifts without a clean trigger. The mix is a policy decision.
Is there a required review frequency in US rules?
The bank AML program rule requires ongoing monitoring and updating customer information on a risk basis. It does not set a fixed calendar, so frequencies are set by each institution's risk-based procedures.