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...

We examine a model in which one firm uses a pricing algorithm that enables faster pricing and multi-period commitment. We characterize a coercive equilibrium in which the algorithmic firm maximizes its profits subject to the incentive compatibility constraint of its rival. By adopting an...

Platforms, retailers, and other firms often offer their own products alongside products sold by competitors. We study the effects of this practice by combining a field experiment that hides brands owned by Amazon (i.e., private labels) from shoppers on Amazon.com with model-based counterfactuals...

This paper uses an aggregative games framework to predict consumer welfare when market structure is endogenously determined. Our main results characterize mergers whose synergies reduce consumer welfare by inducing rivals to exit. The conditions under which such mergers arise are broad,...

We document the effects of a comprehensive set of US retail mergers. On average, prices increase by 1.5% and quantities decrease by 2.3%, with significant heterogeneity in outcomes across mergers. Price changes correlate with the screens codified in the Horizontal Merger Guidelines. Through a...

Antitrust enforcement in the United States has declined since the 1960s. Building on several new datasets, we argue that this decline did not reflect a popular demand for weaker enforcement or any other kind of democratic sanction. The decline was engineered by unelected regulators and judges...

We hand-collect and standardize information describing all 3,055 antitrust lawsuits brought by the Department of Justice (DOJ) between 1971 and 2018. Using restricted establishment-level microdata from the U.S. Census, we compare the economic outcomes of a non-tradable industry in states...

We study the welfare consequences of choice architecture for online privacy using a field experiment that randomizes cookie consent banners. We study three ways in which firms or policymakers can influence choices: (1) nudging users through banner design to encourage acceptance of cookie...

We present a new model of competition between digital media platforms with targeted advertising. The model adds new insights around how user heterogeneity and overlap, along with user and advertiser substitution patterns, determine equilibrium ad load. We apply the model to evaluate the proposed...

Advances in a general-purpose technology (GPT) enable many firms to invent complementary inventions, or co-inventions, making the GPT more valuable. This study examines the empirical implications of a straightforward model in which firms choose either incremental or novel co-invention....