Office: WMX 2666

Phone: 778-782-5406

Short CV

- Econ 305 - (Fall 2008)
Econ 345 - (Spring 2013)
Econ
2021 (at NYU) - (Fall 2018)

- Econ 345 - (Fall 2008)
Econ 305 - (Fall 2013)

- Econ 305 - (Spring 2009)
Econ 808 - (Fall 2013)

- Econ 842 - (Spring 2009)
Econ 842 - (Spring 2014)

- Econ 446 - (Fall 2009) Econ 345 - (Spring 2014)
- Econ 808 - (Fall 2009)
Econ 305 - (Fall 2015)

- Econ 305 - (Spring 2010)
Econ 815 - (Fall 2015)

- Econ 345 - (Spring 2010)
Econ 345 - (Spring 2016)

- Econ 345 - (Fall 2010)
Econ 842 - (Spring 2016)

- Econ 808 - (Fall 2010)
Econ 345 - (Fall 2016)

- Econ 305 - (Spring 2011)
Econ 815 - (Fall 2016)

- Econ 842 - (Spring 2011)
Econ 842 - (Spring 2017)

- Econ 808 - (Fall 2011)
Econ 345 - (Spring 2017)

- Econ 305 - (Spring 2012)
Econ 815 - (Fall 2017)

- Econ 345 - (Fall 2012)
Econ 345 - (Fall 2017)

- Econ 808 - (Fall 2012) Econ 842 - (Spring 2018)
- Econ 305 - (Spring 2013)
Econ 446 - (Spring 2018)

ABSTRACT: Two agents trade an indivisible
asset. They are risk neutral and share a common benchmark dividend model.

However, each has doubts about the
specification of this model. These doubts manifest themselves as a preference
for

robustness (Hansen and Sargent (2008)).
Robust preferences introduce pessimistic drift distortions into the benchmark

dividend process. These distortions
increase with the level of wealth, and give rise to endogenous heterogeneous
beliefs.

Belief heterogeneity allows asset
price bubbles to emerge, as in Scheinkman and Xiong (2003). A novel implication
of

our analysis is that bubbles occur
when wealth inequality increases. Empirical evidence supports this prediction.
Detection

error probabilities suggest that the
implied degree of belief heterogeneity is empirically plausible.

Risk, Uncertainty, and the Dynamics of
Inequality (with Xiaowen Lei) forthcoming in Journal of Monetary Economics

ABSTRACT: This paper studies the dynamics
of wealth inequality in a continuous-time Blanchard/Yaari model. Its key

innovation is to assume that idiosyncratic
investment returns are subject to (Knightian) uncertainty. In response, agents

formulate `robust' portfolio policies (Hansen
and Sargent (2008)). These policies are nonhomothetic; wealthy agents invest

a higher fraction of their wealth in uncertain
assets yielding higher mean returns. This produces an endogenous feedback

mechanism that amplifies inequality. It
also produces an accelerated rate of convergence, which helps resolve a puzzle
recently

identified by Gabaix, Lasry, Lions, and
Moll (2016). We ask the following question - Suppose the US was in a stationary

distribution in 1980, and the world suddenly
became more `uncertain'. Could this uncertainty explain both the magnitude
and

pace of recent US wealth inequality?
Using detection error probabilities to discipline the degree of uncertainty,
we conclude

that an empirically plausible increase
in uncertainty can account for about half of the recent increase in top wealth
shares.

A Behavioral Defense of Rational Expectations

ABSTRACT: This paper studies decision
making by agents who value optimism, but are unsure of their environment.
As in

Brunnermeir and Parker (2005), an agent's
optimism is assumed to be tempered by the decision costs it imposes. As in

Hansen and Sargent (2008), an agent's uncertainty
about his environment leads him to formulate `robust' decision rules. It is

shown that when combined, these two considerations
can lead agents to adhere to the Rational Expectations Hypothesis.

Rather than being the outcome of the sophisticated
statistical calculations of an impassive expected utility maximizer, Rational

Expectations can instead be viewed as a
useful approximation in environments where agents struggle to strike a balance

between doubt and hope.