The Global Impact Investing Network (GIIN) defines impact investing as investment into companies, organizations, and funds with the intention of generating social or environmental impact alongside a financial return. The exact impact will depend on the investor’s goals, while the financial returns can range from below-market to market rate.

Why Do We Care About Impact Investing?
Solving our biggest social problems requires private capital: The United Nations estimates a need for $3.9 trillion a year between now and 2030 to meet the Sustainable Development Goals. Philanthropy and government funding is not enough to meet this need and will require an additional $2.5 trillion a year to fill the gap.

Here is a valuable article on Impact Investing:

https://www.bridgespan.org/insights/library/impact-investing/what-is-impact-investing