An angel investor (also known as a business angel, informal investor, angel funder, private investor, or seed investor) is an individual who provides capital to a business or businesses, including startups, usually in exchange for convertible debt or ownership equity. Angel investors often provide support to startups at a very early stage (when the risk of their failure is relatively high), once or in a consecutive manner, and when most investors are not prepared to back them. In a survey of 150 founders conducted by Wilbur Labs, about 70% of entrepreneurs will face potential business failure, and nearly 66% will face this potential failure within 25 months of launching their company. A small but increasing number of angel investors invest online through equity crowdfunding or organize themselves into angel groups or angel networks to share investment capital and provide advice to their portfolio companies. The number of angel investors has greatly increased since the mid-20th century.
The application of the term "angel" originates in Broadway theater, where it was used to describe wealthy individuals who provided money for theatrical productions that would otherwise have had to shut down. In 1978, William Wetzel, a then-professor at the University of New Hampshire and founder of its Center for Venture Research, completed a pioneering study on how entrepreneurs raised seed capital in the US. He began using the term "angel" to describe the investors who supported them. A similar term, "patron", is commonly used in arts.
Angel investors are often retired entrepreneurs or executives who may be interested in angel investing for reasons that go beyond pure monetary return. These reasons include: wanting to keep abreast of current developments in a particular business arena, mentoring another generation of entrepreneurs, and making use of their experience and networks on a less than full-time basis. Because innovations tend to be produced by outsiders and founders in startups, rather than existing organizations, angel investors provide (in addition to funds) feedback, advice, and contacts.