Several costs, however, emerge from pursuing this model of investment. One major concern is that the bank has become vulnerable to “Trojan multilateralism” or the increased influence of small groups of donors on its health programming.22 32 Indeed, major donors have reported that trust funds are a mechanism for bypassing existing allocation systems and influencing the bank’s priorities.6 This could tilt health funding toward vertical interventions and away from health priorities in the recipient country.22 33 34 For instance, the bank’s Independent Evaluation Group found that the polio buy down programme focused exclusively on providing polio vaccines and not wider health or social services infrastructure4 and that delivery of vertical funds sometimes overburdened weak national health systems.16 Additionally, two key measures that allow IDA to provide performance based allocation for its core projects—the country policy and institutional assessment and worldwide governance indicators—do not apply to trust funds, which further raises the risk that trust funds might not fit the needs of low income countries.3 4