Why are investment companies are regulated so differently from every other kind of company? The multitude of other companies across our diverse spectrum of business endeavors—from software design to clothing retail to food service, and so forth—are regulated by a generic body of securities regulations. What exactly makes an investment company so different from every other kind of company that it alone deserves special securities regulation? The chapter concludes that, whatever the historical rationales for investment company regulation, the most compelling rationale for investment company regulation today is an investment company’s unique organizational structure. An investment fund almost always has a separate legal existence and a separate set of owners from the managers who control it. A fund investor thus relates to her managers in a radically different way from an investor in every other kind of company.