What is the SAR?

Asa Bush

Creative Manager

The Suspicious Activity Report (or SAR) is the main communication channel between financial institutions and law enforcement. SARs provide a detailed summary of any unusual or suspicious financial activity, as investigated by a compliance team. This information is used by law enforcement to “follow the money” in criminal cases, helping put a stop to drug cartels, human trafficking rings, terrorist organizations, and other criminal activity.


Banks aren’t cops, and cops aren’t banks. So how do you find a way to track, monitor, and stop financial crime? You create a way for those two groups to talk to one another. (Securely and privately, of course.)

The Suspicious Activity Report (SAR) is that line of communication. 

Around in one form or another since the Bank Secrecy Act of 1970, SARs capture and record unusual financial activity. Physically, the SAR is a PDF containing 250+ form fields, each of which must be filled out by someone from the bank’s compliance team. Why so long? The SAR is meant to capture any detail a law enforcement official might need to start (or conclude) a criminal investigation.

The SAR PDF is made up of five parts, which we’ll walk through below. 

The Structure of a SAR

Part I: Subject (the “who”)

Information about the subject (as collected by the financial institution’s KYC program). This includes details like names, addresses, SSNs and Tax IDs, as well as things like stated occupation and how long they’ve been a customer or member.

Part II: Suspicious Activity Information (the “what”)

An index and summary of the transactions and financial behavior that the investigator has identified as suspicious or unusual. This includes dates, transaction amounts, monetary instrument types, suspected money laundering methods, and other relevant information.

Part III: Information about Financial Institution where Activity Occurred (the “when” and  “where”)

This section details the type of institution where the suspicious activity occurred (anything from a bank, to a casino, to an insurance company). It pinpoints the role of the institution in the suspicious transactions, and provides all relevant contact information. 

Part IV: Filing institution Contact Information 

Relevant identifying information about the financial institution submitting the report. In many, but not all, cases, this will be the same institution featured in Part III. But even if a bank submits a SAR describing activity that took place within their own systems, additional information (such as the branch name and location) may be required. 

Part V: Suspicious Activity Information: the SAR Narrative (the “why”)

Arguably the most important section of the SAR, the SAR narrative section gives the investigator the chance to explain (in their own words) why they have decided to fill out and submit a SAR. There is an art and a science to crafting a strong narrative, and the stakes are high: law enforcement have acknowledged that a quality SAR narrative can play a big role in “connecting the dots” on sophisticated criminal operations, while a poor narrative can make even quality intel hard to act upon. 

A Note on the SAR Format:

The SAR (helpfully? bafflingly?) contains both a content structure and a process structure. The content structure is what you see above, but an investigator completing the PDF online would use the process structure, technically filling it out in the following order: Part IV, Part III, Part I, Part II, and Part V.

Understanding the importance of the SAR narrative

As you might expect, time-sensitive law enforcement officials use Part V of the Sar (the narrative section) as their starting point. This means that effective SAR narratives are essential for success. So what distinguishes a high-quality SAR narrative? A top-notch narrative will be concise and clear while containing a breakdown of the “who, what, when, where, and why” contained in the report. 

For investigators who fill out the SAR manually, the narrative can feel like an afterthought. They’ve spent hours simply collecting, organizing, and transferring the hard information of the case into the PDF. But the fact of the matter is: the narrative isn’t a place to cut corners. Fortunately, some modern case management systems now auto-populate SAR fields, helpfully reducing the time an investigator spends on manual data entry. This gives the investigator more time to spend on the narrative, where their expertise and input are most valuable.

Who’s FinCEN, and what do they have to do with the SAR?

The Financial Crimes Enforcement Network (more commonly known as FinCEN), is a division of the U.S. Treasury. FinCEN’s mission is to help protect the financial system from things like money laundering. In essence, FinCEN is a government agency tasked with making sure that the laws enacted to fight financial crime are enforced, they have a big role to play in AML efforts. They administer the BSA e-filing system into which all completed SARs are submitted. They then organize and distribute completed SARs to various law enforcement agencies. Though it doesn’t happen often, they are also in charge of any updates or changes to the SAR PDF.  

Why is filing SARs a legal requirement?

Money is a key motivator for all kinds of organized crime. As a result, effectively detecting and deterring money laundering is key to stopping bigger criminal enterprises – everything from drug cartels to human trafficking to terrorism. 

So why bother with compliance departments, audits, the SAR and everything else? In short, because of your right to privacy. Privacy laws exist for a reason, which is why law enforcement doesn’t have 24/7 access to your bank account or your Venmo history. (I mean, unless you’re still sharing your Venmo transaction history publicly, which is a whole separate thing probably worth looking into…)

Compliance is the compromise between customer privacy and the need for financial crime reporting, and was made to provide a balanced approach to AML investigation. 

What happens if you don’t file a SAR like you’re supposed to?

Not filing your SARs isn't a great idea. Because maintaining a robust compliance program is a legal requirement, there are consequences when you don’t do it properly. To make sure that rules are being followed, regulators pop in from time to time to see how things are going. This is called an audit. 

An audit can have a variety of results, ranging from an A+ on your report card to multi-million dollar fines for systemic failures. It’s for this reason that every regulated business must have a dedicated compliance function, and why a quality compliance program is a business advantage.

Does law enforcement really use SARs? How do they fit into criminal investigations?

Absolutely. An effective SAR can act as everything from the start of a major criminal investigation to the “missing link” law enforcement needs to tie the loose ends of an existing investigation together. Money laundering is a crime by itself, but it’s also a downstream effect of all sorts of organized crime. Because of this, effective anti-money laundering efforts are considered one of the surest and most universal of law enforcement methods.

Wrap Up

Yes, the SAR is a humble PDF. But it would be hard to overstate the importance of the SAR in efforts to combat financial crime. Modern AML investigation efforts cannot be said to exist without the SAR, making it possibly one of the most important crime-fighting tools in existence. 

Fun (if unprovable) fact: we’ve heard that Batman is known to carry a SAR in his utility belt.

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