Increasing returns to scale and firms' market power are two potential sources of sunspot expectations in neoclassical models. We show that in New Keynesian models, returns to scale and market power can have fundamentally different implications for broad macroeconomic issues, including...

A challenge facing the literature of equilibrium indeterminacy and sunspot-driven business cycle fluctuations based on increasing returns to scale in production is that the required degree of increasing returns for generating indeterminacy can be implausibly large and rise quickly with the...