What is Structuring?
Structuring is the practice of breaking up cash transactions into smaller amounts to avoid triggering mandatory reporting thresholds.
Structuring is also known as smurfing. In the United States, banks must file a Currency Transaction Report (CTR) for cash transactions over $10,000 in a single day, whether that is one transaction or several related ones. A person who deposits $9,900 several times instead of making a single larger deposit is trying to stay under that threshold and out of view.
Structuring is one of the most common techniques in the placement stage of money laundering. It lets criminals move large amounts of illicit cash into the financial system without creating the paper trail that a single large deposit would.
What are common examples of structuring?
Structuring can be done by one person or spread across a network. Common patterns include the following.
- Several cash deposits just below the reporting threshold on the same day
- Deposits split across multiple branches or ATMs
- Several people depositing cash into the same account
- Cash spread across many accounts controlled by one person
- Small, frequent remittances through money service businesses
- Buying multiple money orders or traveler's checks under the threshold
A simple structuring example looks like this. A customer makes five cash deposits of $9,900 within 24 hours. No single deposit crosses $10,000, but together they total nearly $50,000.
Is structuring illegal if the money is legitimate?
Yes, structuring is illegal in the United States even when the money comes from a legal source. Under federal law, it is a crime to deliberately break up transactions to evade reporting requirements, regardless of where the funds came from. The offense is the intent to avoid the report, not the source of the cash.
Structuring also creates reporting obligations for banks. US institutions must file a suspicious activity report when a transaction appears designed to evade Bank Secrecy Act requirements. Other countries use similar thresholds, such as AUD 10,000 in Australia and CAD 10,000 in Canada, and suspicion must be reported there no matter how small the individual transactions are.
How do financial institutions detect structuring?
Financial institutions detect structuring by looking at transactions together rather than one at a time. Transaction monitoring rules add up a customer's cash activity over a set window and flag patterns that single-transaction checks would miss. A typical structuring rule flags any customer whose individual cash deposits are each under $10,000 but whose total cash deposits exceed $9,000 within 24 hours.
Structuring rules work best when they are tuned to real data. Firms review the last 12 months of transactions to see how often a pattern occurs, then adjust thresholds and time windows to cut false positives. Network analysis adds another layer by linking deposits across accounts, branches, and people who share devices or addresses, which helps catch structuring spread across a group of money mules.
