Final answer:
Angel investors are high-net-worth individuals who invest in businesses as individuals, providing early-stage financial capital in exchange for ownership in the company.
Step-by-step explanation:
High-net-worth individuals who invest in businesses not as a business, but as individuals are known as "angel investors." These individuals are typically affluent and provide early-stage financial capital to small new companies in exchange for owning some portion of the firm. Angel investors are often experienced entrepreneurs themselves and offer not only financial support but also mentorship and expertise to the businesses they invest in.