Regulators consist of government agencies that exist to enforce and monitor compliance with the rules of a jurisdiction. Financial markets are regulated by a number of agencies.
In the U.S., the agencies consist of:
- Securities and Exchange Commission (SEC): The SEC was created in 1934 after the Great Market Crash of 1929, during the days of the ensuing U.S. Depression, to protect investors, to maintain fair, orderly, and efficient markets, and to facilitate capital formation in the U.S. securities markets.
- Commodity Futures Trading Commission (CFTC): The CFTC was created in 1974 to regulate commodity futures and options markets in the United States. (Prior to that time, futures markets were regulated by the Commodity Exchange Authority (CEA), a division of the U.S. Department of Agriculture). The CFTC's mandate has been renewed and expanded several times since 1974, most recently by the Commodity Futures Modernization Act of 2000 (CFMA), and by the Dodd-Frank Act, which added swaps and OTC derivatives to the CFTC's mandate.
- Office of the Comptroller of the Currency, U.S. Department of the Treasury (OCC): The OCC charters, regulates and supervises all national banks, and also supervises national affiliates of foreign banks. 
- Board of Governors of the Federal Reserve System (Fed): Founded in 1913 to provide stability to the nation's monetary and financial system, the Fed monitors and regulates banking institutions. Its dual mandate is to provide price stability and to maintain full employment. 
- Federal Deposit Insurance Corporation (FDIC): The FDIC was created through the Glass-Steagall Act of 1933 to maintain stability and confidence in the nation's banks and thrift institutions. The FDIC insures deposits, audits member banks for soundness, and manages receiverships.
- Farm Credit Administration (FCA): The Federal agency responsible for regulating credit and financial services for participants in the U.S. agriculture industry and in rural areas of the country. The agency was created during the Great Depression of the 1930s, and its authority was amended by the Farm Credit Act of 1971.
- Federal Housing Finance Agency (FHFA): The Federal agency created in 2008 to regulate Government Sponsored Enterprises (GSEs) Fannie Mae, Freddie Mac, and Federal Home Loan Banks. 
- About the OCC. Office of the Comptroller of the Currency.
- Overview of the Federal Reserve System. Federal Reserve.
- About FDIC. Federal Deposit Insurance Corporation.
- FCA in Brief. Farm Credit Administration.
- About FHFA. Federal Housing Finance Agency.