What has driven the bank to increasingly turn to trust funds to finance health projects? Firstly, the flexibility of trust funds allows the bank to raise funds from a diverse group of donors for priority countries, while retaining the bank’s trusted financial management services.6 16 17 Core IBRD/IDA programmes can accept contributions only from governments, but trust funds can accept funding from the private sector. This is especially important for vertical (disease specific) funds: corporations like Exxon Mobil and pharmaceutical companies have contributed to health trust funds, and the Bill and Melinda Gates Foundation was the second largest donor to the recent replenishment of Gavi, the Vaccine Alliance.6 19 New financing mechanisms for many vertical funds also entice donors by allowing them to make programme and budgetary decisions. The Global Fund and Gavi, for example, have their own legal charters and a board of directors on which for-profit private sector representatives have voting power.20 Finally, trust funds can channel funding to countries that are not members of the bank or do not choose to invest in global public goods.6 For instance, the Avian and Human Influenza Facility raised $126m for avian influenza surveillance and control in 2006-13 and allocated some of this funding to “weak link” countries that were not prioritising influenza control interventions.21