Structuring (Smurfing)

1 Introduction

Structuring (also called "smurfing") is the practice of breaking down large financial transactions into smaller amounts to avoid regulatory reporting thresholds. In the US, banks must file a Currency Transaction Report (CTR) for any transaction over $10,000. Structuring is a federal crime under 31 U.S.C. § 5324, regardless of whether the underlying funds are legitimate.

$10,000

US CTR reporting threshold

€10,000

EU reporting threshold

5 yrs

Max prison sentence (US)

2 Structuring Simulator - Interactive

Total Amount to Launder

$15K $50,000 $200K

Number of Deposits

2 6 20

Number of Days

1 7 days 30

Transaction Breakdown

Detection Dashboard

Avg. Transaction Size $8,333

$10K CTR Limit →

Threshold Proximity Score 72%

How close deposits cluster below the threshold

SAR Filing Risk HIGH

3 Detailed Analysis

Legal Framework

Structuring is a crime independent of the source of funds. Even legitimate money deposited in a pattern designed to evade reporting requirements violates 31 U.S.C. § 5324. Banks must file Suspicious Activity Reports (SARs) when they detect structuring patterns, even if no individual transaction exceeds $10,000. The FinCEN requires aggregation of related transactions within a single business day.

Detection Methods

Modern AML systems use aggregation rules that track cumulative cash deposits by customer over rolling periods (1 day, 3 days, 7 days). ML models analyze velocity patterns, geographic distribution (multiple branches), and behavioral changes. Banks also train tellers to identify structuring behaviors like asking about reporting thresholds.

Red Flags

Multiple cash deposits just below $10,000 within a short time window
Deposits made at different branches on the same day
Customer inquiring about reporting thresholds or CTR filing
Multiple persons (smurfs) making deposits into the same account