You can spot money laundering by watching for transactions and behavior that don’t line up with a person’s stated income or business: cash deposits broken into amounts just under $10,000, accounts that funds pass through without stopping, shell companies with revenue but no operations, and customers who get evasive when asked routine questions. The United Nations Office on Drugs and Crime estimates that laundered money accounts for 2% to 5% of global GDP each year, and the signs below are what compliance teams, business owners, and alert employees look for.
Transaction Patterns That Don’t Add Up
The clearest signals sit in the numbers. Banks file a Currency Transaction Report for every cash transaction over $10,000, and criminals know it.1Financial Crimes Enforcement Network. Notice to Customers: A CTR Reference Guide That threshold shapes most of the suspicious patterns you’ll see.
Structuring is the most common evasion tactic. Someone makes several deposits of $9,500 or $9,800 across a few days instead of depositing the full sum at once. The intent is to stay under $10,000. Financial institutions are required to file a Suspicious Activity Report when a transaction involves at least $5,000 and appears designed to evade reporting requirements,2Financial Crimes Enforcement Network. Frequently Asked Questions Regarding Suspicious Activity Reporting Requirements and structuring is itself a federal crime even when the underlying money is clean.3Office of the Law Revision Counsel. 31 U.S. Code 5324 – Structuring Transactions to Evade Reporting Requirement Prohibited
Other transaction signals worth watching:
- Large cash deposits that don’t match the customer’s known income, occupation, or business type.
- Rapid pass-through activity, where funds land in an account and get wired out or withdrawn almost immediately, so the account functions as a pipeline rather than a place to hold money.
- Repeated round-number deposits or transfers ($5,000, $9,000) with no business explanation.
- Wires to or from countries on the Financial Action Task Force’s grey or black lists, which flag jurisdictions with weak anti-money-laundering controls. As of February 2026, over 20 countries appear on the FATF’s increased monitoring list.4Financial Action Task Force (FATF). Black and Grey Lists5Financial Action Task Force (FATF). Jurisdictions Under Increased Monitoring – 13 February 2026
Trade-based laundering hides in the invoicing rather than the wire. An exporter bills $150,000 for goods worth $100,000. The importer pays the inflated amount, sells the goods at market value, and the $50,000 difference crosses borders looking like ordinary trade revenue. Under-invoicing works in reverse. Customs authorities struggle to verify the true value of every shipment, which is what makes the scheme workable.
Behavior That Gives Launderers Away
How a customer acts often tells you more than any single number. Someone who refuses to provide identification, gives vague or shifting explanations for a large transaction, or gets nervous during routine questions is signaling something. Compliance officers see it constantly, and it triggers a closer look even when the amounts alone wouldn’t.
Third-party involvement without a clear reason is another common sign. A person sending someone else to make deposits, or a business receiving payments from entities with no apparent connection to what it does, may be hiding who actually controls the money. Sudden changes in transaction patterns, or opening multiple accounts at different branches over a short period, fit the same profile.
Then there are customers who probe the rules. Asking whether a specific transaction will trigger a report, or trying to talk an employee out of a verification step, is a deliberate attempt to work around the system. Bank staff are trained to treat those conversations as red flags on their own.
Business and Real Estate Signs
Shell companies are the workhorse of laundering. A business with no employees, no physical office, and no clear product or service that somehow generates significant revenue exists to move money. Ownership chains that stretch across multiple jurisdictions make the true owner nearly impossible to identify, which is the point.
Legitimate businesses can also front for illicit funds. The clues include revenue that doesn’t match the industry or location, cash receipts far above what similar businesses report, and a gap between what a company claims to do and what it actually does. A laundromat or car wash reporting $2 million in annual revenue in a small town is the kind of inconsistency that draws attention.
Real estate absorbs large sums in a single purchase, which makes it a favorite for the final stage of laundering. FinCEN has long required title insurance companies to report all-cash purchases by legal entities in designated metropolitan areas through Geographic Targeting Orders.6Financial Crimes Enforcement Network. Geographic Targeting Order Covering Title Insurance Company In August 2024, FinCEN announced a final rule expanding residential real estate transparency nationwide, requiring certain closing professionals to report non-financed transfers that pose a high risk for illicit finance.7Financial Crimes Enforcement Network. FinCEN RRE Fact Sheet Red flags in property deals include all-cash purchases through a legal entity, prices well above market value, and properties bought and resold quickly with no renovation.
Cryptocurrency Signs
Digital assets have opened new laundering channels, and FinCEN has published specific indicators to watch for.8Financial Crimes Enforcement Network. Advisory on Illicit Activity Involving Convertible Virtual Currency
- Use of mixing or tumbling services, which break the link between sending and receiving wallet addresses so blockchain transactions become harder to trace.
- Rapid conversion between multiple cryptocurrencies with no investment purpose, which breaks the chain of custody across blockchains.
- Transactions involving wallet addresses tied to darknet marketplaces or other known illegal activity.
- Funds arriving from a wallet whose blockchain history points back to an illicit source, such as a known criminal marketplace.
Cryptocurrency exchanges that operate as money services businesses carry the same SAR filing obligations as banks. Blockchain transactions leave a permanent public record, so crypto laundering is traceable in ways cash never is, provided someone is looking.
How to Report Suspected Money Laundering
Financial institutions file SARs electronically through FinCEN’s BSA E-Filing System within 30 calendar days of first detecting suspicious activity. If no suspect has been identified by then, the institution has an additional 30 days to identify the person, but the report cannot be delayed beyond 60 days from initial detection.9Financial Crimes Enforcement Network. FinCEN Suspicious Activity Report Electronic Filing Instructions The institutions required to file include banks, casinos, money services businesses, broker-dealers, mutual funds, insurance companies, and mortgage lenders.
Once a SAR is filed, the institution and everyone involved in preparing it are legally prohibited from telling anyone connected to the transaction that a report was made. This tipping-off ban covers directors, officers, employees, and agents, along with any government employee who learns of the report, and violating it carries its own penalties.10Office of the Law Revision Counsel. 31 U.S. Code 5318 – Compliance, Exemptions, and Summons Authority If an institution receives a subpoena for SAR information, it must refuse to produce the report and notify FinCEN. The confidentiality exists so a suspect can’t destroy evidence, move money, or flee.
Reporting as an Individual
You don’t have to work at a bank to report suspected laundering. You can contact law enforcement directly, or reach the compliance department of the financial institution involved. If you’re witnessing potential laundering at your workplace, federal law offers specific protections.
The Anti-Money Laundering Act shields whistleblowers from retaliation, including termination, demotion, and harassment.11Office of the Whistleblower Ombuds. Anti-Money Laundering Act (AMLA) Whistleblowers whose information leads to a successful enforcement action with monetary sanctions above $1 million may be eligible for awards of 10% to 30% of the collected sanctions.12Office of the Law Revision Counsel. 31 USC 5323 – Whistleblower Incentives and Protections The awards can be substantial because laundering penalties routinely reach into the millions.
What Happens After a Report
The reporting framework feeds a serious criminal statute. The main federal money laundering law covers financial transactions with proceeds from illegal activity when the person knows the funds are dirty and intends to promote the crime, conceal the source, or evade taxes. Conviction carries up to 20 years in prison and a fine of up to $500,000 or twice the value of the property involved, whichever is greater.13Office of the Law Revision Counsel. 18 U.S. Code 1956 – Laundering of Monetary Instruments A companion statute targets anyone who knowingly engages in a monetary transaction over $10,000 using property derived from illegal activity, carrying up to 10 years in prison and fines up to twice the property’s value.14Office of the Law Revision Counsel. 18 USC 1957 – Engaging in Monetary Transactions in Property Derived From Specified Unlawful Activity Structuring is a separate offense, prosecutable even when the underlying money is legitimate,3Office of the Law Revision Counsel. 31 U.S. Code 5324 – Structuring Transactions to Evade Reporting Requirement Prohibited which is how otherwise law-abiding people sometimes end up charged.
A conviction also triggers criminal forfeiture of any property involved in the offense or traceable to it, including bank accounts, real estate, and vehicles.15Office of the Law Revision Counsel. 18 U.S. Code 982 – Criminal Forfeiture Once a report is in FinCEN’s hands, the trail the launderer worked to hide becomes the government’s evidence.