The following analysis indicates the wide range of deals in design phases in developing countries, ranging in terms of country, sector, size of returns, and evaluation methodology. Emerging from the analysis, the recorded discussions in a one-day workshop with practitioners, and indepth interviews with stakeholders from the contracted deals, the authors have identified five key issue areas in the design and implementation of impact bonds, which the following sections will explore. 1. Identifying appropriate interventions and service providers. 2. Managing relationships with government and donor outcome funders. 3. Identifying metrics and structuring payments. 4. Developing the operating model, structuring the vehicle, and raising capital. 5. Implementing the impact bond and measuring impact.