Q: What is the filing deadline for a SAR?
A: A FinCEN SAR shall be filed no later than 30 calendar days after the date of the initial detection by the reporting financial institution of facts that may constitute a basis for filing a report. If no suspect is identified on the date of such initial detection, a financial institution may delay filing a FinCEN SAR for an additional 30 calendar days to identify a suspect, but in no case shall reporting be delayed more than 60 calendar days after the date of such initial detection. In situations involving violations that require immediate attention, such as terrorist financing or ongoing money laundering schemes, the financial institution shall immediately notify by telephone an appropriate law enforcement authority in addition to filing timely a FinCEN SAR. Financial institutions wishing voluntarily to report suspicious transactions that may relate to terrorist activity may call FinCEN’s Financial Institutions Hotline at 1-866-556-3974 in addition to filing timely a FinCEN SAR.
This is addressed in the "FinCEN Suspicious Activity Report Electronic Filing Requirements" guide, Attachment C.