A Suspicious Activity Report, or SAR, is the mechanism by which a financial firm tells the government that something looks wrong. It is a confidential filing, made on a deadline, and it is one of the more consequential and misunderstood obligations in anti-money-laundering compliance.
Firms subject to the Bank Secrecy Act must file a SAR when they detect a transaction that they know, suspect, or have reason to suspect involves illicit funds, is designed to evade reporting requirements, has no apparent lawful purpose, or involves certain other red flags. The standard is suspicion, not proof, which means the judgment call sits with the firm's monitoring and its people.
A defining feature of SARs is confidentiality: it is generally unlawful to tip off the subject that a SAR has been or will be filed. The customer is not told. This tipping-off prohibition is strict, and a firm's staff must understand it, because an inadvertent disclosure can itself be a violation. SAR handling is therefore a matter of controlled, need-to-know process.
SARs must generally be filed within a set number of days of detecting the suspicious activity, and late or missed filings are a common and serious finding. That makes the firm's ability to detect, escalate, and decide quickly, not just its willingness to file, the thing that has to work.
Suspicion is the standard, and silence is the rule.
Greenridge L&C Advisors is a compliance consultancy, not a law firm. This is general information, not legal advice.