An angel investor (angel) is an individual that provides investment capital into companies. A typical angel investor is an independently wealthy individual who has made their success either via high-level corporate positions, or via starting and growing their own firm. Angels often like investing in early stage companies and founders, as a way to "give back" to the community and business world. Oftentimes, the angels enjoy the process of investing in companies and helping them achieve success.
Sometimes an angel investor will join a group called an angel investment network, to share their capital and business savvy, in return for reducing their risk in any one investment. As a collective unit, the angel investment network will review business plans and decide which investments to pursue. Angel investment networks function as a sort of mutual fund for angel investors. By investing in the fund, angels can diversify their capital and also expose themselves to more opportunities. In addition, the larger amounts that investment networks can accumulate allows them to pursue opportunities that individual angels could not.