Monetary policy is neutral even with fixed prices if free entry determines product variety optimally, as in Dixit and Stiglitz (1977). Entry substitutes for price flexibility in the welfare-based price index when individual prices are sticky. In response to aggregate demand expansions, the intensive (quantity produced of each good) and ex tensive (number of goods being produced) margins move in offsetting ways, leaving aggregate production unchanged. Price stickiness thus generates deviations from monetary neutrality only in conjunction with entry frictions: when variety is not optimally determined (preferences are not Dixit-Stiglitz) or when entry is subject to sunk costs and lags. Wage stickiness instead implies nonneutrality even in the frictionless-entry benchmark.

We show an equivalence result in the representative-agent New-Keynesian model after demand, wage-markup and correlated price-markup and TFP shocks: assuming sticky prices and flexible wages yields identical allocations for GDP, consumption, labor, inflation and interest rates to the opposite case—flexible prices and sticky wages. This equivalence arises with identical price and wage Phillips-curve slopes and generalizes to any slopes' pair whose sum and product are identical. Equilibrium profits and wages are, however, substantially different; equivalence breaks when these factor-distributional implications matter for aggregate allocations, e.g. in New-Keynesian models with heterogeneous agents, endogenous firm entry, and non-constant returns to scale.

This paper argues that limited asset market participation is crucial in explaining U.S. macroeconomic performance and monetary policy before the 1980s and their changes thereafter. In an otherwise conventional sticky-price model, standard aggregate demand logic is inverted at low enough asset market participation: interest rate increases become expansionary, and passive monetary policy ensures equilibrium determinacy and maximizes welfare. This suggests that Federal Reserve policy in the pre-Volcker era was better than conventional wisdom implies. We provide empirical evidence consistent with this hypothesis and study the relative merits of changes in structure and shocks for reproducing the conquest of the Great Inflation and the Great Moderation.