What is the term for private investors who provide financing for new or risky small venture startups?

The term that accurately describes private investors who provide financing for new or risky small venture startups is "angels." Angel investors often use their personal finances to invest in early-stage companies, taking on the associated risks in exchange for equity ownership or convertible debt in the startup.

These investors typically offer not only capital but also mentorship and advice, leveraging their experience to help the business grow. The involvement of angel investors can be crucial for startups that may struggle to secure financing from traditional sources like banks, especially when they are in their initial phases or lack an established track record.

In contrast, while venture capitalists also invest in startups, they tend to operate through formal firms and typically invest larger sums in more mature startups. "Equity partners" usually refer to investors who join a partnership structure in a firm, while "financial backers" is a broader term that can encompass various types of investors without specifically indicating early-stage focus. Together, this highlights why "angels" is the term that best fits the definition provided in the question.