Suspicious activity report
SARAlso called suspicious transaction report, STR
A suspicious activity report is a confidential filing a regulated firm makes to its national financial intelligence unit when it knows or suspects money laundering, terrorist financing or other financial crime. In the US it goes to FinCEN, in the UK to the National Crime Agency. Firms must not tell the customer a report has been made.
How it works
Most reports start as alerts from transaction monitoring, staff referrals or screening. Investigators review the activity, gather customer and transaction data and decide whether suspicion exists. In the UK the nominated officer or MLRO decides whether to report. US banks must file within 30 calendar days of initial detection, extended to no more than 60 days when no suspect is identified. Firms keep the report and supporting records confidential.
Reports give law enforcement intelligence it cannot gather elsewhere, and they feed investigations, asset recovery and typology work. Failure to report is a criminal offence in the UK and a common basis for enforcement in the US. Supervisors look at report quality, timeliness and the link between monitoring alerts and filings. Tipping off the customer is itself an offence.
The rules
Requires banks to report suspicious transactions involving at least $5,000, generally within 30 calendar days of initial detection.
US banksMakes failure to disclose knowledge or suspicion of money laundering an offence and provides for disclosures to the National Crime Agency.
Regulated sector firms and their staffRequires obliged entities to report suspicious transactions and activity to the national FIU, replacing the reporting rules of the fourth AML directive.
EU obliged entitiesCommon questions
Is a SAR the same as an STR?
They are the same concept. The US and UK use suspicious activity report. Many other jurisdictions, including EU member states, use suspicious transaction report. Both are filed with the national financial intelligence unit.
Does filing a SAR mean the customer is guilty?
No. A SAR records suspicion, not proof of a crime. It is intelligence for law enforcement. Many reports never lead to an investigation, but they can contribute to wider cases and typology analysis.
Can a firm tell a customer it has filed a SAR?
No. Disclosing a SAR, or an investigation, to the customer or anyone else in a way that could prejudice an investigation is prohibited. In the UK this is the tipping off offence; US rules require SAR confidentiality.
What changed in US SAR rules in October 2025?
FinCEN issued FAQs stating firms are not required to run a separate review after filing a SAR to check whether activity continued. They may rely on risk-based policies. The FAQs did not change the filing deadlines.
Our coverage
News and analysis on AML from RegTech Post.
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