This paper examines the role of intermediaries in Social Impact Bond financing agreements. Social Impact Bonds are a financial innovation designed to save public entities money and promote social good by funding preventative social services with private capital. To date, Social Impact Bonds in the U.S. have utilized private sector intermediaries to structure contracts, manage service providers, and ultimately to mitigate financial risk. In this paper I present the context and progress of Social Impact Bonds in the U.S. and use financial analysis to estimate value from the investor's perspective in the Rikers Island Social Impact Bond. I then discuss the ability of intermediaries to affect and communicate value to investors. I found that intermediaries are intrinsic to the success of Social Impact Bonds. This paper anticipates their effect on the mode and scope of Social Impact Bond proliferation by exploring their role in the assessment of risk and value.