Suspicious Activity Report
A Suspicious Activity Report (SAR) is a confidential report that US financial institutions are required to file with the Financial Crimes Enforcement Network (FinCEN) when they detect a transaction or pattern of transactions that may involve money laundering, fraud, terrorist financing, or other financial crimes.
SARs were introduced by the Bank Secrecy Act regulatory framework in the 1990s to create a structured pipeline of financial intelligence from the private sector to law enforcement. Before the SAR regime, different agency forms existed — the Treasury's Form 90-22.47 for banks and the SEC's Form SAR-SF for broker-dealers — which were consolidated into a single BSA SAR form in 2012, now filed electronically through FinCEN's BSA E-Filing system.
Financial institutions subject to SAR filing obligations include federally insured banks, thrifts, credit unions, broker-dealers, futures commission merchants, mutual funds, money services businesses, insurance companies offering certain products, casinos, and certain other entities. The filing obligation is triggered when an institution knows, suspects, or has reason to suspect that a transaction involves funds derived from illegal activity, is designed to evade BSA reporting or recordkeeping requirements (structuring), has no lawful purpose or is not the type of transaction the customer would normally be expected to engage in, or involves use of the institution to facilitate criminal activity.
The SAR must be filed within 30 days after the date of initial detection of the suspicious activity, or within 60 days if additional time is needed to identify a subject. No minimum dollar threshold applies to SAR filing for most transaction types, though a $5,000 threshold ($25,000 for some categories) triggers a mandatory filing obligation — below those amounts, filing remains optional when the institution suspects illegal activity. The SAR narrative — a plain-language description of the suspicious activity — is considered the most analytically valuable component of the filing for law enforcement purposes.
SAR filing is subject to strict confidentiality rules. Under 31 U.S.C. Section 5318(g), it is illegal for an institution or any of its officers, employees, or agents to notify the subject of a SAR that the filing has been made or is being contemplated. This prohibition, known as the tipping-off restriction, is designed to prevent subjects from destroying evidence or moving funds before law enforcement can investigate. Institutions are shielded from civil liability for SAR filings made in good faith under the BSA's safe harbor provision.
FinCEN maintains the BSA database and shares SAR and Currency Transaction Report data with law enforcement agencies including the FBI, DEA, IRS Criminal Investigation, Homeland Security Investigations, and OFAC. The data also supports FinCEN's own financial intelligence analysis function, which issues advisories, geographic targeting orders, and typology reports to help financial institutions recognize emerging money laundering methods and high-risk actor profiles.