Commercial banks are subject to regulation that restricts their investments. When banks are concerned for their reputation, however, they could self-regulate and invest more efficiently. Hence, a shadow banking that arises to avoid regulation has the potential to improve welfare. Still,...

We study a market with free entry and exit of firms who can produce high-quality output by making a costly but efficient initial unobservable investment. If no learning about this investment occurs, an extreme "lemons problem" develops, no firm invests, and the market shuts down. Learning...

Banks are optimally opaque institutions. They produce debt for use as a transaction medium (bank money), which requires that information about the backing assets - loans - not be revealed, so that bank money does not fluctuate in value, reducing the efficiency of trade. This need for opacity...

Short-term collateralized debt, such as demand deposits and money market instruments - private money, is efficient if agents are willing to lend without producing costly information about the collateral backing the debt. When the economy relies on such informationally-insensitive debt, firms...

The CDC reports that 1.13 million Americans have died of COVID-19 through June of 2023. I use a model of the impact over the past three years of vaccines and private and public behavior to mitigate disease transmission during the COVID-19 pandemic in the United States to address two questions....

To understand how best to combat COVID-19, we must understand how deadly is the disease. There is a substantial debate in the epidemiological lit- erature as to whether the fatality rate is 1% or 0.1% or somewhere in between. In this note, I use an SIR model to examine why it is difficult to...