I derive a general condition on consumer behavior ensuring that, in a standard model of demand-determined output, any path of inflation and output that is implementable via interest rate policy is also implementable through time-varying uniform transfers. In an analytical model with occasionally binding borrowing constraints, my condition holds generically. In a quantitative heterogeneous-agent model, the transfer policy that closes any given demand shortfall is furthermore well characterized by a small number of measurable sufficient statistics. My results extend to environments with investment if transfers are supplemented by another standard fiscal tool: bonus depreciation.

Macroeconomists increasingly use external sources of exogenous variation for causal inference. However, unless such external instruments (proxies) capture the underlying shock without measurement error, existing methods are silent on the importance of that shock for macroeconomic fluctuations. We show that, in a general moving average model with external instruments, variance decompositions for the instrumented shock are interval-identified, with informative bounds. Various additional restrictions guarantee point identification of both variance and historical decompositions. Unlike SVAR analysis, our methods do not require invertibility. Applied to U.S. data, they give a tight upper bound on the importance of monetary shocks for inflation dynamics.