A Development Impact Bond, or DIB, is a results-based investment instrument that involves three parties: a private investor, an outcome payer, and an implementing partner/service provider. In practice, a DIB can have more than one of each type of partner. The private investor—usually a fund or group of investors—gives money to carry out a development project that promises certain social outcomes. The service provider, usually a nonprofit organisation, is responsible for the project and its outcomes. If the outcomes are achieved, the investor is paid back the capital plus interest by the outcome payer, usually a philanthropic funder or organisation. DIBs allow the focus in development aid to shift from inputs (e.g. the number of text books for students) to outcomes (e.g. an increase in students’ learning outcomes).