This document discusses the regulatory and contractual aspects of implementing social impact bonds. It provides details on the key elements that should be included in: 1) The instruction agreement between the government authority and social service provider which outlines the social program, services, duration, payments and termination conditions. 2) The loan agreement between investors and the social service provider covering the loan amount, repayment terms based on program outcomes, and information rights. 3) The service agreement between the evaluator, social service provider and authority regarding the outcome measurement process, data collection, reporting and dispute resolution.