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Report
The Risk of Becoming Risk Averse: A Model of Asset Pricing and Trade Volumes
We develop a new general equilibrium model of asset pricing and asset trading volume in which agents? motivations to trade arise due to uninsurable idiosyncratic shocks to agents? risk tolerance. In response to these shocks, agents trade to rebalance their portfolios between risky and riskless assets. We study a positive question ? When does trade volume become a pricing factor? ? and a normative question ? What is the impact of Tobin taxes on asset trading on welfare? In our model, economies in which marketwide risk tolerance is negatively correlated with trade volume have a higher risk ...
Report
The End of Privilege: A Reexamination of the Net Foreign Asset Position of the United States
The US net foreign asset position has deteriorated sharply since 2007 and is currently negative 65 percent of US GDP. This deterioration primarily reflects changes in the relative values of large gross international equity positions, as opposed to net new borrowing. In particular, a sharp increase in equity prices that has been US-specific has inflated the value of US foreign liabilities. We develop an international macro finance model to interpret these trends, and we argue that the rise in equity prices in the United States likely reflects rising profitability of domestic firms rather than ...
Report
Sophisticated monetary policies
In standard approaches to monetary policy, interest rate rules often lead to indeterminacy. Sophisticated policies, which depend on the history of private actions and can differ on and off the equilibrium path, can eliminate indeterminacy and uniquely implement any desired competitive equilibrium. Two types of sophisticated policies illustrate our approach. Both use interest rates as the policy instrument along the equilibrium path. But when agents deviate from that path, the regime switches, in one example to money; in the other, to a hybrid rule. Both lead to unique implementation, while ...
Working Paper
External and Public Debt Crises
The recent debt crises in Europe and the U.S. states feature similar sharp increases in spreads on government debt but also show important differences. In Europe, the crisis occurred at high government indebtedness levels and had spillovers to the private sector. In the United States, state government indebtedness was low, and the crisis had no spillovers to the private sector. We show theoretically and empirically that these different debt experiences result from the interplay between differences in the ability of governments to interfere in private external debt contracts and differences in ...
Report
What Will be the Economic Impact of COVID-19 in the US? Rough Estimates of Disease Scenarios
This note is intended to introduce economists to a simple SIR model of the progression of COVID-19 in the United States over the next 12-18 months. An SIR model is a Markov model of the spread of an epidemic in a population in which the total population is divided into categories of being susceptible to the disease (S), actively infected with the disease (I), and recovered (or dead) and no longer contagious (R). How an epidemic plays out over time is determined by the transition rates between these three states. This model allows for quantitative statements regarding the tradeoff between the ...
Conference Paper
The transition to a new economy after the Second Industrial Revolution
During the Second Industrial Revolution, 1860?1900, many new technologies, including electricity, were invented. After this revolution, however, several decades passed before these new technologies diffused and measured productivity growth increased. We build a quantitative model of technology diffusion which we use to study this transition to a new economy. We show that the model implies both slow diffusion and a delay in growth similar to that in the data. Our model casts doubt, however, on the conjecture that this experience is a useful parallel for understanding the productivity paradox ...
Working Paper
On the optimality of transparent monetary policy
We analyze the optimal design of monetary rules. We suppose there is an agreed upon social welfare function that depends on the randomly fluctuating state of the economy and that the monetary authority has private information about that state. We suppose the government can constrain the policies of the monetary authority by legislating a rule. In general, well-designed rules trade-off the need to constrain policymakers from the standard time consistency problem arising from the temptation for unexpected inflation with the desire to give them flexibility to react to their private information. ...
Journal Article
Are Phillips curves useful for forecasting inflation?
This study evaluates the conventional wisdom that modern Phillips curve-based models are useful tools for forecasting inflation. These models are based on the non-accelerating inflation rate of unemployment (the NAIRU). The study compares the accuracy, over the last 15 years, of three sets of inflation forecasts from NAIRU models to the naive forecast that at any date inflation will be the same over the next year as it has been over the last year. The conventional wisdom is wrong; none of the NAIRU forecasts is more accurate than the naive forecast. The likelihood of accurately predicting a ...
Report
Understanding 100 Years of the Evolution of Top Wealth Shares in the U.S.: What is the Role of Family Firms?
We use a simple random growth model to study the role of changing dynamics of family firms in shaping the evolution of top wealth shares in the United States over the course of the past century. Our model generates a time path for top wealth shares. The path is remarkably similar to those found by Saez and Zucman (2016) and Gomez (2019) when the volatility of idiosyncratic shocks to the value of family firms is similar to that found for public firms by Herskovic, Kelly, Lustig, and Van Nieuwerburgh (2016). We also show that consideration of family firms contributes not only to overall wealth ...
Report
How Deadly is COVID-19? Understanding the Difficulties with Estimation of its Fatality Rate
To understand how best to combat COVID-19, we must understand how deadly is the disease. There is a substantial debate in the epidemiological literature 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 estimate the fatality rate from the disease and how long we might have to wait to resolve this question absent a large-scale randomized testing program. I focus on uncertainty over the joint distribution of the fatality rate and the initial number of active cases at the start of the epidemic around January ...