Table of contents
Structuring is the deliberate splitting of a large sum of cash into smaller deposits, withdrawals or transfers so that each one stays below a reporting threshold, such as the 10,000 dollar currency transaction report limit in the United States. It is a federal crime in its own right under 31 U.S.C. 5324, whether or not the money is criminal in origin.
Structuring is a placement-stage technique: it is how cash gets into the financial system without triggering the report that would put it in front of a financial intelligence unit. The stages of money laundering entry sets out where it fits; this entry covers what it is, how it is detected, and what the law says.
Structuring meaning: what the law prohibits
In the United States, 31 U.S.C. 5324 makes it an offence to structure or assist in structuring any transaction with a financial institution for the purpose of evading the reporting requirements of the Bank Secrecy Act, above all the currency transaction report (CTR) that a bank must file for cash transactions over 10,000 dollars in a day. The offence is the evasion, not the source of the funds: a business owner who splits legitimate cash takings into 9,500 dollar deposits to avoid the paperwork is committing structuring. Other jurisdictions treat the same conduct as a money-laundering red flag rather than a standalone crime, and reporting thresholds differ, for example 10,000 euros for cash in much of the EU.
Structuring deposits: how it looks in practice
- Several cash deposits just under the threshold on consecutive days, or at several branches on the same day.
- Deposits split across accounts held by the same person, family members or a business and its owner.
- Purchases of money orders, cashier’s cheques or prepaid cards in amounts that avoid the recordkeeping thresholds for those instruments.
- Withdrawals structured the same way, so cash leaves without a report.
- Smurfing: the same pattern run by several people on the launderer’s behalf, which is structuring with helpers.
How structuring is detected
Structuring defeats a single-transaction rule by design, so detection aggregates: total cash per customer per day and per rolling period across branches and accounts, counts of transactions in a threshold band (for example 9,000 to 9,999 dollars), and links between accounts that share owners, addresses or devices. Banks also file suspicious activity reports on suspected structuring; there is no dollar minimum for a SAR on this pattern, and FinCEN’s guidance names it as one of the most common SAR typologies.
How Zyphe detects structuring
Zyphe’s transaction monitoring rules read velocity fields, sums and counts over 1 hour, 24 hours, 7 days and 30 days, and 24-hour net flow, so a threshold-band rule aggregates across a customer’s accounts and time rather than looking at one deposit. Alerts arrive at the transaction monitoring alert triage desk with the fired rules attached, and the rule can be backtested on your own history before it goes live to see how many genuine customers it would catch.
Written by Michelangelo Frigo (Co-Founder at Zyphe) Reviewed September 18, 2026 Michelangelo Frigo is a privacy and identity infrastructure expert and co-founder of Zyphe.