Modern theories of aggregate supply are built on the foundation that firms set prices and commit to producing whatever the market demands. We remove this strategic restriction and allow firms to choose supply functions, mappings that describe the prices charged at each quantity of production. Theoretically, we characterize firms’ optimal supply function choices in general equilibrium and study the resulting implications for aggregate supply. Aggregate supply flattens under lower inflation uncertainty, higher idiosyncratic demand uncertainty, and less elastic demand. Quantitatively, our theory can rationalize the flattening of aggregate supply during the Great Moderation and steepening during the 1970s and 2020s.

Is credit expansion a sign of desirable financial deepening or the prelude to an inevitable bust? We study this question in modern US data using a structural VAR model of 10 monthly frequency variables, identified by heteroskedasticity. Negative reduced-form responses of output to credit growth are caused by endogenous monetary policy response to credit expansion shocks. On average, credit and output growth remain positively associated. “Financial stress” shocks to credit spreads cause declines in output and credit levels. Neither credit aggregates nor spreads provide much advance warning of the 2008–2009 crisis, but spreads improve within-crisis forecasts.

We study the nonlinear pricing of goods whose usage generates revenue for the seller and of which buyers can freely dispose. The optimal price schedule is a multi-part tariff, featuring tiers within which buyers pay a marginal price of zero. We apply our model to digital goods, for which advertising, data generation, and network effects make usage valuable, but monitoring legitimate usage is infeasible. Our results rationalize common pricing schemes including free products, free trials, and unlimited subscriptions. The possibility of free disposal harms producer and consumer welfare and makes both less sensitive to changes in usage-based revenue and demand.