Structuring—also known as "smurfing"—is the practice of breaking up large cash transactions into smaller amounts to avoid triggering Currency Transaction Reports (CTRs). In the United States, financial institutions must file CTRs for cash transactions exceeding $10,000. Structuring is illegal and is often an indicator of money laundering.
What Makes Structuring Detection Challenging
Detecting structuring isn't as simple as flagging transactions just under $10,000. Sophisticated actors vary their amounts, spread transactions across multiple accounts or branches, and mix structured deposits with legitimate activity.
Key Patterns to Detect
1. Threshold Proximity
Look for transactions in the "danger zone"—typically $8,000 to $9,999. While not definitive on their own, clusters of transactions in this range warrant investigation.
2. Velocity Analysis
Calculate aggregate deposits over rolling time windows. A customer making five $9,000 deposits across five days is just as suspicious as a single $45,000 deposit.
3. Round Number Avoidance
Legitimate transactions often result in round numbers. Structurers sometimes deliberately use odd amounts ($9,347, $8,892) to appear more natural, but this creates its own pattern.
4. Geographic Dispersion
Deposits made at multiple branches on the same day suggest an attempt to avoid detection. Map transaction locations and flag unusual geographic patterns.
Building a Detection Tool
With OpsBuilder, you can generate a structuring detection tool in seconds. Simply describe what you need:
"Create a Python tool that analyzes bank transaction data for structuring patterns. Flag cash deposits between $8,000-$9,999, calculate aggregate deposits over 1-day and 7-day windows, identify same-day deposits at multiple branches, and output a risk score for each customer."
OpsBuilder generates working code that you can immediately run against your data—no weeks of development time required.
Beyond Basic Detection
Advanced structuring detection should also consider:
- Customer history and baseline behavior
- Relationship to other accounts (beneficial ownership)
- Timing patterns (day of week, time of day)
- Teller patterns (same teller processing multiple suspicious transactions)
The goal isn't just to find structuring—it's to identify it early enough to file timely SARs and support potential prosecutions.