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. According to a survey of 150 founders conducted by Wilbur Labs, approximately 70% of entrepreneurs risk facing potential business failure, and nearly 66% risk facing this potential failure within 25 months of launching their company. A small but growing 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.