We present estimates of 4 and 8 firm concentration ratios by industry and in weighted aggregate form for the manufacturing sector for Chinese enterprises for 2002 and 2007. These are then compared to available estimates for the same years and industrial classification for the US. These...

The U.S. business sector has under-invested relative to Tobin's Q since the early 2000's. We argue that declining competition is partly responsible for this phenomenon. We use a combination of natural experiments and instrumental variables to establish a causal relationship between competition...

We analyze private fixed investment in the U.S. over the past 30 years. We show that investment is weak relative to measures of profitability and valuation - particularly Tobin's Q, and that this weakness starts in the early 2000's. There are two broad categories of explanations: theories that...

This paper uses a rich panel dataset of Spanish manufacturing firms (1990-2006) and a propensity score reweighting estimator to show that multinational firms acquire the most productive domestic firms, which, on acquisition, conduct more product and process innovation (simultaneously adopting...

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...

A rollup is a series of acquisitions through which a financial sponsor consolidates ownership. Increasingly, this strategy is shaping economically important markets, but historically, it has escaped antitrust enforcement. We study this phenomenon in the anesthesia industry, site of the first...

While prior studies tend to view hospital integration through the lens of horizontal consolidation, I provide an analysis of its vertical aspects. I examine the effect of hospital acquisitions in New York State on the distribution of market share for major cardiac procedures across providers in...