(USA) A regulation under the Securities Act of 1933 that exempts limited offers and sales of securities from registration if the offering satisfies certain requirements as to the number and nature of investors and the value of the offering. Advertising and resale are restricted. In general, Rule 504 of Reg D is used for offerings of $1 million or less; Rule 505 of Reg D is used for offerings of $5 million or less, with no more than 35 purchasers who are not Accredited Investors; and Rule 506 of Reg D is used for offerings over $5 million, with no more than 35 purchasers who are not Accredited Investors, but who must be either sophisticated or represented by a Purchaser Representative. See 'Accredited Investors' and 'Purchaser Representative'.