背景介绍：raise capital有2种方式： 私募和公开发行。可见 https://www.sec.gov/smallbusiness
Wiki的介绍 Regulation D
https://en.wikipedia.org/wiki/Regulation_D_(SEC)
SEC对于Regulation D介绍：
https://www.sec.gov/fast-answers/answers-regdhtm.html
Regulation D是不需要再SEC注册售卖证券的法规。
简而言之，是私募条款
教材的标题是，Private Offering Exemptions： Regulation D
SEC写到：
Under the federal securities laws, any offer or sale of a security must either be registered with the SEC or meet an exemption. Regulation D under the Securities Act provides a number of exemptions from the registration requirements, allowing some companies to offer and sell their securities without having to register the offering with the SEC.
Rule 504 of Regulation D
https://www.sec.gov/fast-answers/answers-rule504.html
Rule 504 of Regulation D provides an exemption from the registration requirements of the federal securities laws for some companies when they offer and sell up to $5,000,000 of their securities in any 12-month period.
