Most developing economies rely on foreign capital to finance their infrastructure needs. These projects are usually structured as long-term (25-35 year) franchises that pay in local currency. If investors evaluate their returns in terms of foreign currency, exchange rate volatility introduces risk that may reduce the level of investment below what would be socially optimal. In this paper, we propose a mechanism with very general features that hedges exchange rate fluctuation by adjusting the concession period. Such mechanism does not imply additional costs to the government and could be offered as a zero-cost option to lenders and investors exposed to currency fluctuations. We illustrate the general mechanism with three alternative specifications and use data from a 25-year highway franchise to simulate how they would play out in eight different countries that exhibit diverse exchange rate trajectories.