Regardless of the difficulty in measurement, the amount of money laundered each year is in the billions (US dollars) and poses a significant policy concern for governments. As a result, governments and international bodies have undertaken efforts to deter, prevent and apprehend money launderers. Financial institutions have likewise undertaken efforts to prevent and detect transactions involving dirty money, both as a result of government requirements and to avoid the reputational risk involved.
Money laundering often occurs in three steps: first, cash is introduced into the financial system by some means (“placement”), the second involves carrying out complex financial transactions in order to camouflage the illegal source (“layering”), and the final step entails acquiring wealth generated from the transactions of the illicit funds (“integration”). Some of these steps may be omitted, depending on the circumstances; for example, non-cash proceeds that are already in the financial system would have no need for placement.
Money laundering takes several different forms although most methods can be categorized into one of a few types. These include "bank methods, smurfing [also known as structuring], currency exchanges, and double-invoicing."
- Structuring: Often known as "smurfing," it is a method of placement by which cash is broken into smaller deposits of money, used to defeat suspicion of money laundering and to avoid anti-money laundering reporting requirements. A sub-component of this is to use smaller amounts of cash to purchase bearer instruments, such as money orders, and then ultimately deposit those, again in small amounts.
- Bulk cash smuggling: Physically smuggling cash to another jurisdiction, where it will be deposited in a financial institution, such as an offshore bank, with greater bank secrecy or less rigorous money laundering enforcement.
- Cash-intensive businesses: A business typically involved in receiving cash will use its accounts to deposit both legitimate and criminally derived cash, claiming all of it as legitimate earnings. Often, the business will have no legitimate activity.
- Overpurchasing: This is where a launderer buys an item from a private seller, pays with an excess check, and is paid back the overflow. This remainder can be claimed as legal spending, and be used however the launderer likes. Ex.- "I would like to buy your product at $300. However, I would like to pay with a $2000 check, and for you to send me back the $1700"
- Trade-based laundering: Under- or over-valuing invoices in order to disguise the movement of money.
- Shell companies and trusts: Trusts and shell companies disguise the true owner of money. Trusts and corporate vehicles, depending on the jurisdiction, need not disclose their true, beneficial, owner.
- Bank capture: Money launderers or criminals buy a controlling interest in a bank, preferably in a jurisdiction with weak money laundering controls, and then move money through the bank without scrutiny.
- Casinos: An individual will walk in to a casino with cash and buy chips, play for a while and then cash in his chips, for which he will be issued a check. The money launderer will then be able to deposit the cheque into his bank account, and claim it as gambling winnings. In the United States, federal law requires that chips that are purchased must be different in appearance from chips that are won. If the casino is controlled by organized crime and the money launderer works for them, the launderer will lose the illegally obtained money on purpose in the casino and be paid with other funds by the criminal organization.
- Real estate: Real estate may be purchased with illegal proceeds, then sold. The proceeds from the sale appear to outsiders to be legitimate income. Alternatively, the price of the property is manipulated; the seller will agree to a contract that under-represents the value of the property, and will receive criminal proceeds to make up the difference.
- Black salaries: Companies might have unregistered employees without a written contract who are given cash salaries. Black cash might be used to pay them.
 EnforcementAnti-money laundering (AML) is a term mainly used in the financial and legal industries to describe the legal controls that require financial institutions and other regulated entities to prevent, detect and report money laundering activities. Anti-money laundering guidelines came into prominence globally as a result of the formation of the Financial Action Task Force (FATF) and the promulgation of an international framework of anti-money laundering standards. These standards began to have more relevance in 2000 and 2001 after FATF began a process to publicly identify countries that were deficient in their anti-money laundering laws and international cooperation, a process colloquially known as "name and shame."
An effective AML program requires a jurisdiction to have criminalized money laundering, given the relevant regulators and police the powers and tools to investigate; be able to share information with other countries as appropriate; and require financial institutions to identify their customers, establish risk-based controls, keep records, and report suspicious activities.
 Criminalizing money launderingThe elements of the crime of money laundering are set forth in the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances and Convention against Transnational Organized Crime. It is knowingly engaging in a financial transaction with the proceeds of a crime for the purpose of concealing or disguising the illicit origin of the property.
 The role of financial institutionsToday, most financial institutions globally, and many non-financial institutions, are required to identify and report transactions of a suspicious nature to the financial intelligence unit in the respective country. For example, a bank must verify a customer's identity and, if necessary, monitor transactions for suspicious activity. This is often termed as KYC – "know your customer." This means, to begin with, knowing the identity of the customers, and further, understanding the kinds of transactions in which the customer is likely to engage. By knowing one's customers, financial institutions will often be able to identify unusual or suspicious behavior, termed anomalies, which may be an indication of money laundering.
Bank employees, such as tellers and customer account representatives, are trained in anti-money laundering and are instructed to report activities that they deem suspicious. Additionally, anti-money laundering software filters customer data, classifies it according to level of suspicion, and inspects it for anomalies. Such anomalies would include any sudden and substantial increase in funds, a large withdrawal, or moving money to a bank secrecy jurisdiction. Smaller transactions that meet certain criteria may be also be flagged as suspicious. For example, structuring can lead to flagged transactions. The software will also flag names that have been placed on government "blacklists" and transactions involving countries that are thought to be hostile to the host nation. Once the software has mined data and flagged suspect transactions, it alerts bank management, who must then determine whether to file a report with the government.
 Value of enforcement costs and associated privacy concernsThe financial services industry has become more vocal about the rising costs of anti-money laundering regulation, and the limited benefits that they claim it appears to bring. One commentator wrote that "[w]ithout facts, [anti-money laundering] legislation has been driven on rhetoric, driving by ill-guided activism responding to the need to be "seen to be doing something" rather than by an objective understanding of its impact on predicate crime. The social panic approach is justified by the language used – we talk of the battle against terrorism or the war on drugs..." The Economist newspaper has become increasingly vocal in its criticism of such regulation, particularly with reference to countering terrorist financing, referring to it as a "costly failure," although concedes that the rules to combat money laundering are more effective.
However, no precise measurement of the costs of regulation balanced against the harms associated with money laundering, and, given the evaluation problems involved in assessing such an issue, it is unlikely the effectiveness of terror finance and money laundering laws could be determined with any degree of accuracy. Government-linked economists have noted the significant negative effects of money laundering on economic development, including undermining domestic capital formation, depressing growth, and diverting capital away from development.
Data privacy has also been raised as a concern. A European Union working party, for example, has announced a list of 44 recommendations to better harmonize, and if necessary pare back, the money laundering laws of EU member states to comply with fundamental privacy rights. In the United States, groups such as the American Civil Liberties Union have expressed concern that money laundering rules require banks to report on their own customers, essentially conscripting private businesses "into agents of the surveillance state."
In any event, many countries are obligated by various international instruments and standards, such as the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances, the Convention against Transnational Organized Crime, and the United Nations Convention against Corruption, and the recommendations of the Financial Action Task Force on Money Laundering to enact and enforce money laundering laws in an effort to stop narcotics trafficking, international organized crime, and corruption. Other countries, such as Mexico, which are faced with significant crime problems believe that anti-money laundering controls could help curb the underlying crime issue.