In the United States under the Securities Act of 1933, any offer to sell securities must either be registered with the United States Securities and Exchange Commission (SEC) or meet certain qualifications to exempt them from such registration. Regulation D (or Reg D) contains the rules providing exemptions from the registration requirements, allowing some companies to offer and sell their securities without having to register the securities with the SEC.[1] A Regulation D offering is intended to make access to the capital markets possible for small companies that could not otherwise bear the costs of a normal SEC registration. The regulation is found under Title 17 of the Code of Federal Regulations, part 230, Sections 501 through 508. The legal citation is 17 C.F.R. §230.501 et seq.

Reg D also affects individual savings and money market accounts with banks and credit unions, and any other person or entity that wishes to sell securities. Regulation D consistently exempts certain persons and entities within its rules, describing them as "accredited investors," (generally this includes banks, certain other organizations, and people making more than $200,000 per year or with a net worth of over $1,000,000). Regulation D also exempts certain offerings of equity from many of the regulatory requirements that impose costs upon standard public offerings.