On June 25, 2015, the Global Impact Investing Network (GIIN) and Cambridge Associates issued “Introducing the Impact Investing Benchmark,” the first comprehensive analysis of the financial performance of market rate impact investing funds. The benchmark comprises 51 private investment funds providing a broad view of the field. The report, and the data itself, generated a great deal of discussion in the impact investing community. To capture some of that discussion SSIR teamed up with the GIIN to publish the following “Up for Debate” on impact investing. To kick off the discussion we are publishing an essay by GIIN CEO Amit Bouri, “A Coming of Age for Impact Investing.” That essay is followed by responses from leading thinkers and practitioners in impact investing.