Banks detect money laundering through a combination of mandatory "Know Your Customer" (KYC) onboarding, AI-powered transaction monitoring software, and human analysis of red flags. Automated systems flag unusual patterns—like rapid cash turnover or structuring (breaking large deposits into smaller ones)—prompting compliance teams to file Suspicious Activity Reports (SARs) with authorities.
Red flags of money laundering
Unusual financial activity that deviates from a customer's normal transaction patterns. Large cash deposits with no clear justification for their origin. Evasive or defensive responses when questioned about transactions. Discrepancies in provided information or documentation.
AML checks involve verifying customer identities, monitoring transactions, and identifying high-risk individuals in banking to prevent financial crimes.
✅ Example of a Money Laundering Offence: A company in Thailand sets up fake supplier contracts to launder money through legitimate-looking business transactions. The funds are then transferred to various bank accounts across Malaysia, Indonesia, and Vietnam to obscure their true origin.
Placement
This is arguably the most vulnerable phase for those laundering money, as criminals have to move large bulk amounts of money into a legitimate financial system.
Warning signs include:
How Long Do Anti-Money Laundering Checks Take? AML check completion times can differ greatly depending on a number of variables. Automated AML screenings can be completed in seconds, whilst manual AML screening can take a few hours to a few weeks on average.
Signs of money laundering include unusual transaction patterns (rapid movement, large cash amounts, complex structures, high-risk jurisdictions), customer behavior (evasiveness, providing false info, reluctance to ID), and inconsistent business activity (e.g., cash-heavy businesses with unexplained high turnover or losses). Key indicators involve using shell companies, third-party payments, virtual assets, and frequent, unexplained fund movements.
Under the law, solicitors must confirm their clients' identities and check the source of any funds involved in legal transactions. Solicitors may also need to carry out checks in other cases, such as when giving tax advice, even if no money or property is being exchanged.
You can transfer large amounts of money, but transactions over $10,000, especially in cash or structured deposits, trigger mandatory reporting (like IRS Form 8300 or Bank Secrecy Act (BSA) reports), not necessarily taxes, to fight money laundering. Banks file reports for cash over $10k (CTR) or suspicious activity (SAR) if they see patterns to avoid reporting (structuring), which can flag accounts even for smaller amounts like $200 if part of a pattern.
SAR filings can be triggered by a variety of activities that appear suspicious such as large cash deposits or withdrawals, frequent wire transfers to high-risk countries, structuring transactions to avoid reporting requirements, and any transaction that doesn't seem to have a legitimate business purpose.
To prove a violation of § 1956(a)(1), the prosecutor must prove, either by direct or circumstantial evidence, that the defendant knew that the property involved was the proceeds of any felony under State, Federal or foreign law.
Under the Bank Secrecy Act (BSA), financial institutions are required to assist U.S. government agencies in detecting and preventing money laundering, and: Keep records of cash purchases of negotiable instruments; File reports of cash transactions exceeding $10,000 (daily aggregate amount); and.
Money can be laundered through peer-to-peer payments, online money transfers and more, all while using a proxy server to disguise the launderers' identities. Criminals can also hold phony online auctions or convert their dirty money into currency for gaming and gambling before withdrawing newly cleaned money.
Large, incoming funds transfers are received on behalf of a foreign client, with little or no explicit reason. Funds transfer activity is unexplained, repetitive, or shows unusual patterns. Payments or receipts with no apparent links to legitimate contracts, goods, or services are received.
Money laundering is most easily identified during the placement stage, as the injection of large amounts of cash into the legitimate financial system may draw attention from officials.
Banks can freeze your account if they suspect fraud, money laundering, illegal activity or if there's been a court order. If it's happened to you, it can be really upsetting and confusing, especially if you haven't heard directly from your bank to explain why.
You can deposit any amount of cash without being automatically flagged if it's under $10,000 in a single transaction, but banks must report deposits of $10,000 or more to the IRS via a Currency Transaction Report (CTR). While large, legitimate deposits are fine, making multiple deposits to stay under $10,000 (structuring) is illegal and triggers Suspicious Activity Reports (SARs), leading to potential account freezes or law enforcement scrutiny, so transparency with your bank is best for large sums.
Comprehensive customer due diligence programs are banks' most effective weapons against being used unwittingly to launder money or to support terrorist financing.
The Layering Stage
Layering is the second stage of money laundering. Its purpose is to make the money as hard to detect as possible, further moving it away from its illegal source(s). It can often be the most complex stage of the laundering process.
It's defined by intent and actions. Any funds, regardless of size, derived from illegal activities and moved to conceal their source or nature can qualify. Transactions over $10,000 trigger stricter reporting under the Bank Secrecy Act, but smaller amounts can still constitute money laundering if illicitly handled.
Financial crimes like money laundering and embezzlement are under intense scrutiny by law enforcement agencies, making it critical for individuals and business owners to stay aware of potential signs of investigation.