How it works

A SAR starts when monitoring, a frontline referral, or an investigation surfaces unusual activity. An analyst reviews the customer's profile, transaction history and any supporting evidence, decides whether the activity is suspicious, and, if it is, files a report with a narrative explaining who, what, when, where and why. SARs are confidential: the customer must not be told that a report was made.

Requirements by jurisdiction

• US: Banks must file with FinCEN for suspicious transactions of at least $5,000 where a suspect can be identified (31 CFR 1020.320); money services businesses use a $2,000 threshold (31 CFR 1022.320). The SAR is due within 30 calendar days of initial detection, extendable to 60 days if no suspect is identified, and supporting records are kept for five years. FinCEN's October 2025 FAQs, issued with the federal banking agencies, state that a separate post-filing "continuing activity" review is not required and that the long-standing 90-day continuing-activity timeline is optional.

• EU: Obliged entities report suspicious transactions to their national FIU. Under the AML Regulation (EU) 2024/1624, which applies from 10 July 2027, the compliance officer is responsible for reporting under Article 69.

• UK: Reports go to the UK Financial Intelligence Unit at the National Crime Agency. Firms needing a defence against money laundering (DAML) before proceeding face a 7-working-day notice period and, if refused, a 31-calendar-day moratorium.

Common challenges

Teams struggle with high alert volumes, inconsistent narrative quality, and deciding when an alert has reached "initial detection." The FFIEC manual notes that a system flag alone is not initial detection; the clock starts once the institution knows or has reason to suspect the activity is reportable. Tipping-off risk complicates customer outreach during investigations.

How teams handle it in practice

Mature programs use a defined escalation path from alert to case to filing decision, standard narrative templates, and second-level quality review before submission. They track filing deadlines per case and keep a clear audit trail of the evidence considered. Compliance platforms like Corsa can automate evidence gathering and draft narratives for analyst review, but the filing decision stays with designated staff.