World Food Prices, the Terms of Trade-Real Exchange Rate Nexus, and Monetary Policy

How should monetary policy respond to large fluctuations in world food prices? We study this question in an open economy model in which imported food has a larger weight in domestic consumption than abroad and international risk sharing can be imperfect. A key novelty is that the real exchange rate and the terms of trade can move in opposite directions in response to world food price shocks. This exacerbates the policy trade-off between stabilizing output prices vis a vis the real exchange rate, to an extent that depends on risk sharing and the price elasticity of exports. Under perfect risk sharing, targeting the headline CPI welfare-dominates targeting the PPI if the variance of food price shocks is not too small and the export price elasticity is realistically high. In such a case, however, targeting forecast CPI is a superior choice. With incomplete risk sharing, PPI targeting is clearly a winner.