Securities regulation in the United States is the field of U.S. law that covers transactions and other dealings with securities. The term is usually understood to include both federal and state-level regulation by governmental regulatory agencies, but sometimes may also encompass listing requirements of exchanges like the New York Stock Exchange and rules of self-regulatory organizations like the Financial Industry Regulatory Authority (FINRA).

A security is a tradable financial asset. The term commonly refers to any form of financial instrument, but its legal definition varies by jurisdiction. In some countries and languages people commonly use the term "security" to refer to any form of financial instrument, even though the underlying legal and regulatory regime may not have such a broad definition. In some jurisdictions the term specifically excludes financial instruments other than equities and fixed income instruments. In some jurisdictions it includes some instruments that are close to equities and fixed income, e.g., equity warrants.