We combine a structural model with cross-sectional micro data to identify the causes and consequences of rising concentration in the US economy. Using asset prices and industry data, we estimate realized and anticipated shocks that drive entry and concentration. We validate our approach by...

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...