Exposure to foreign currency financing can create financial fragility in developing countries, since depreciations increase debt burdens. This exposes nations to significant exchange rate (FX) risk, increasing the volatility and cost of foreign financial flows while undermining long-term stability. While public development banks (PDBs) are key in providing local currency alternatives, they are often constrained by the same global monetary structures and high domestic interest rates that limit their lending capacity. Unlike commercial banks, PDBs depend on external financing, which becomes prohibitively expensive in high-interest environments and undermines their ability to provide affordable domestic loans. To circumvent this, PDBs often use international concessional financing, yet this exposes them to the very FX risks that constrain their local currency operations and necessitate strategies for mitigation. The paper develops an institutional case study of the Uganda Development Bank (UDB), based on applied analysis and incubation work led through the FiCS Lab in close collaboration with UDB, the Bank of Uganda, development finance institutions, policymakers, and the FiCS FX Working Group. The analysis draws on UDB’s balance-sheet structure, lending operations, and Climate Finance Facility pipeline, focusing on how the bank uses foreign-currency credit lines to finance local-currency climate lending. The paper uses FX modelling, stress-testing, and option-pricing techniques, together with legal, operational, and stakeholder engagement work, to assess alternative instrument designs developed during the FiCS incubation process. The paper proposes an innovative currency risk-sharing scheme to enable the UDB to scale local currency finance while managing its currently unhedged FX exposure by distributing FX risk across UDB, a hedge provider, and a tail-risk guarantor. Because conventional hedging through currency swaps is too costly, UDB presently bears the full FX risk of its foreign currency liabilities. The proposed scheme introduces a middle-ground solution by partially hedging this exposure and protecting UDB against large, unexpected depreciations of the Ugandan shilling through a tail-risk FX guarantee. FX risk below a specified threshold remains with UDB, while any appreciation beyond the threshold is transferred to the guarantor. The instrument is more affordable for UDB than full hedging and, on average, is profitable for the guarantor. By capping severe FX losses, the scheme stabilises UDB’s capital position and supports the sustainable provision of local currency climate finance. The guarantee may be provided by an external donor or multilateral financial institution. Please see the instrument mechanism below.