Discussion Paper

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Chasing the trillions: what MDB lending can - and cannot - mobilise

Zattler, Jürgen K. / Kathrin Berensmann / Yabibal Walle
Discussion Paper (11/2026)

Bonn: German Institute of Development and Sustainability (IDOS)

ISBN: 978-3-96021-297-3
DOI: https://doi.org/10.23661/idp11.2026

This paper examines how additional private financial resources can be mobilised through the use of multilateral development bank (MDB) funds. It focuses on identifying the leverage potential of different financing instruments, improving their mobilisation efficiency, and examining how greater leverage can promote development outcomes while safeguarding the financial sustainability of MDBs. Its contribution is a comparative synthesis that brings together mobilisation mechanisms, differences in the public resources and risks underlying leverage ratios, and development impact. The analysis covers six categories: debt instruments, equity instruments, risk-transfer instruments, guarantees, advisory services and policy-based lending. It compares their characteristics, including the level of intervention, mobilisation mechanisms, constraints addressed and time horizons. It also distinguishes transaction-level private direct and indirect mobilisation from broader catalytic effects arising through market development, institutional strengthening and policy reforms.
The comparison shows why instruments cannot be assessed by a single leverage ratio. MDB lending, guarantee exposure and expenditure on advisory services represent different commitments of public resources and risk. Similarly, private finance linked to a transaction cannot be measured in the same way as subsequent investment enabled by policy reform. Available evidence therefore indicates differences in mobilisation potential rather than an established empirical ranking of instruments. The paper argues that leveraging efficiency can be increased by moving to more powerful approaches and by better targeting instruments to binding investment constraints. It examines how this can enhance the development impact and financial viability of MDB/DFI portfolios through two channels: a financial/portfolio efficiency channel and a development/catalytic channel. However, a high leverage ratio does not necessarily indicate superior performance. It may reflect investment in easier markets, weak additionality or an understatement of public risk. Conversely, a lower ratio may be consistent with greater additionality in a fragile market or pioneering sector. These findings highlight the importance of assessing leverage alongside additionality, development impact and financial sustainability. Using concessional funds through blended finance instruments can be costly and can reduce the resources available for other development priorities.
Therefore, the development finance institutions (DFIs) must strictly apply the additionality principle and further operationalise the principle of using minimum concessionality. If interpreted too generously, there is a risk of creating leverage without sufficient development impact. The paper provides specific recommendations for refining the use of financing instruments and integrating transaction-level support into a broader market-shaping approach that draws on the strengths of policy-based lending and technical assistance. Higher leverage should not be pursued as an end in itself; its value depends on its contribution to additional development impact.

Dr Jürgen Karl Zattler is a distinguished non-resident fellow at the Center for Global Development in Washington, DC and a non-resident research fellow at the German Institute of Development and Sustainability (IDOS) in Bonn. Until October 2023, he was Director General at the German Ministry for Economic Cooperation and Development (BMZ). Prior to that, he served as the Executive Director representing Germany at the World Bank.

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