This paper examines the evolving structure and competition dynamics of the rapidly growing market for foundation models, with a focus on large language models (LLMs). We describe the technological characteristics that shape the AI industry and have given rise to fierce competition among the...

Forward-looking investments determine the resilience of firms' supply chains. Such investments confer externalities on other firms in the production network. We compare the equilibrium and optimal allocations in a general equilibrium model with an arbitrary number of vertical production tiers....

This paper explores how different margins of market share are related to markups. Using merged microdata on producers and consumers, we document that a firm's market share is mainly related to its number of customers, while its price-cost markup is associated only with its average sales per...

Empirical studies have found that enhanced foreign competition can encourage or discourage innovation. To address this relationship, I examine a market structure in which a small number of large multi-product oligopolists compete with a large number of small single-product firms in the same...

This paper studies the effect of nonlinear pricing on markups and misallocation. We develop a general equilibrium model of firms that are allowed to set a quantity-dependent pricing schedule--contrary to the typical assumption in macroeconomic models. Without the restriction to linear pricing,...

"We prove that the change in welfare of a representative consumer is summarized by the current and expected future values of the standard Solow productivity residual. The equivalence holds if the representative household maximizes utility while taking prices parametrically. This result justifies...

A number of papers have solved for the optimal dynamic portfolio strategy when expected returns are time-varying and trading is costly, but only for agents with myopic utility. Non-myopic agents benefit from hedging against future shocks to the investment opportunity set even when transaction...

Motivated by the recent National Association of Realtors (NAR) settlement, this note examines the effects of reduced real estate agent commissions on home prices, housing turnover, and consumer welfare. Using a calibrated dynamic structural search model of the housing market, we explore how...

The pharmaceutical market has experienced a massive wave of vertical integration between pharmacy benefit managers (PBMs) and health insurers in recent years. Using a unique dataset on insurer-PBM contracts, we document increasing vertical integration in Medicare Part D-vertically integrated...

Using textual analysis of earnings conference calls, we quantify firms' supply chain risk and its sources. Our proxy for supply chain risk exhibits large cross-sectional and time-series variation that aligns with reasonable priors and is unprecedently high during the Covid-19 pandemic. In...