Suspicious activity report

In financial regulation, a suspicious activity report (SAR) or suspicious transaction report (STR) is a report made by a financial institution about suspicious or potentially suspicious activity as required under laws designed to counter money laundering, financing of terrorism and other financial crimes. The criteria to decide when a report must be made varies from country to country, but generally, it is any financial transaction that either a) does not make sense to the financial institution; b) is unusual for that particular client; or c) appears to be done only for the purpose of hiding or obfuscating another, separate transaction.

Source: Wikipedia — Suspicious activity report (CC BY-SA 4.0)