All Working Papers
with Menaka Hampole, Dimitris Papanikolaou, and Bryan Seegmiller, Revise and Resubmit at the Quarterly Journal of Economics. Updated July 2025
We use advances in natural language processing to construct new measures of workers’ task-level exposure to artificial intelligence (AI) and machine learning from 2010 to 2023, capturing variation across firms, occupations, and time. Tasks with higher AI exposure subsequently experience reduced labor demand. To interpret these patterns, we develop a model that separates direct substitution from indirect reallocative effects of labor-saving technologies. Two variables summarize the impact of AI on within-firm labor demand: the mean exposure of an occupation’s tasks, which depresses demand, and the concentration of exposure in a few tasks, which offsets losses by enabling workers to reallocate effort. Using an instrument based on historical university hiring networks, we find causal evidence consistent with these predictions. Despite strong substitution at the task level, overall employment effects are modest, as reduced demand in exposed occupations is offset by productivity-driven increases in labor demand at AI-adopting firms.
with Leonid Kogan, Dimitris Papanikolaou, and Bryan Seegmiller. Revise and Resubmit at the Review of Economic Studies. Updated July 2024
We develop measures of labor-saving and labor-augmenting technology exposure using textual analysis of patents and job tasks. Using US administrative data, we show that exposure to labor-saving technologies negatively affects the earnings of exposed workers. This negative effect is pervasive across both blue- and white-collar workers and across workers of different ages or earnings relative to their peers. In contrast, labor-augmenting technologies have a heterogeneous impact on exposed workers. While the wage bill paid to affected groups rises, this increase is driven primarily by an increase in employment, while earnings rise for new entrants but decline for incumbent workers. This decline is primarily present among white-collar, older, and higher-paid workers, highlighting the importance of vintage-specific human capital. Last, we find positive spillovers of both types of innovation at the industry level, benefiting other workers in the same industry who are not directly exposed to these innovations.
with Brice Green, Leonid Kogan, and Dimitris Papanikolaou, Last Updated December 2025
Using U.S. administrative data, we find that technology-driven creative destruction in the product market passes through to worker earnings. The passthrough to incumbent worker earnings is both asymmetric and concentrated: profit drops from rival innovations lead to proportionally greater earning declines and changes in the likelihood of job destruction than profit gains from their own firm's innovations, while top workers are significantly more exposed than the average worker. We develop an endogenous-growth model with monopsonistic labor markets and worker heterogeneity that replicates this asymmetry and the distribution of earnings risk. Creative destruction exposes high-income workers to concentrated downside risk while offering lower-income workers upward mobility, shaping the welfare consequences of innovation policy.
Note: This paper builds on and subsumes previous work in an earlier paper, entitled Technological Innovation and Labor Income Risk, which was joint work with Leonid Kogan, Dimitris Papanikolaou, and Jae Song
with Sung Je Byun and Johnathan Loudis, Revise and Resubmit at the Journal of Financial Economics, Updated December 2025
We construct a Broad Market Factor (BMF), which is a proxy for the value-weighted equity return on all firms in the US economy (public and private). The BMF differs from the standard Value-weighted Market Factor (VMF), which reflects the value-weighted equity return on public firms. We define the difference between the VMF and the BMF to be the Idiosyncratic Financial Factor (IFF). The IFF carries no risk premium and is uncorrelated with all macroeconomic proxies for investor marginal utility we consider. CAPM betas and, consequently, discount rates are underestimated when measured with respect to the VMF compared to the BMF for most portfolios. Size factors become redundant and the size anomaly is resolved when the VMF is replaced by the BMF in standard factor models. The intertemporal risk-return relation is substantially stronger when one replaces the VMF with the BMF. The unifying explanation for these results is that the IFF adds unpriced risk to the VMF, distorting both cross-sectional and time-series estimates of exposure to priced market risk.
with J. Carter Braxton, Kyle Herkenhoff, Chengdai Huang, Michael Nattinger, and Jonathan Rothbaum
We estimate the evolution of permanent and transitory income risk across the income distribution and over time using newly-digitized and longitudinally-linked Census-IRS tax returns. Since the 1970s, the variance of permanent income shocks (i.e., permanent income risk) has increased by over 65% for those in the top 5% of the income distribution. Using capitalized interest and dividend income, we document that high income households save significantly more in response to increases in permanent income risk compared to lower income households. To examine the implications of rising permanent income risk among high income households we integrate our income process into a Bewley-Huggett-Aiyagari model and calibrate the model to be consistent with our savings elasticities. We find that increasing permanent income risk among high income households has put downward pressure on interest rates and increased wealth inequality.
with Janet Gao, Shan Ge, and Cristina Tello-Trillo, Revise and Resubmit at the Review of Financial Studies.
Employer-sponsored health insurance is a significant component of labor costs. We examine how insurance premiums causally affect worker outcomes across the income distribution. For identification, we instrument premiums using idiosyncratic variation in insurers' recent losses. Analyzing US administrative data, we find that higher premiums adversely affect low-income workers but not high-income workers. Following premium increases, low-income workers face higher rates of job separation, unemployment, large earnings losses, and transitions to staffing arrangements, as well as lower wage growth even when retained. In contrast, high-income workers experience minimal adverse effects and even benefit on some dimensions.
with Yinchu Zhu, Walter P. Heller Memorial Award Winner. Updated June 2025
We propose a simple alternative to linear-in-parameters quantile regressions for modeling conditional distributions. Our approach parameterizes the conditional quantile function using a single “location” quantile (typically the median), with other quantiles constructed by adding or subtracting sums of exponentially affine functions—quantile spacings. This generalized location-scale specification preserves the computational tractability of linear quantile regression, avoids quantile crossing, and imposes a scale restriction motivated by a changes-in-changes model (Athey and Imbens, 2006). The method integrates easily with other econometric frameworks, including instrumental variable models, machine learning, quantile factor models, and nonlinear synthetic controls. We illustrate the approach using U.S. employer–employee matched data to study the effects of mass layoffs on the earnings distribution of displaced workers. We find that average effects—consistent with prior literature—mask a substantial thickening of the left tail, especially during downturns. These findings highlight large welfare costs that are not captured by changes in mean earnings alone.
with Fiona Greig, Anna Madamba, Guillermo Carranza, Cormac O'Dea, Taha Choukhmane, May 2024
We propose criteria that employers can use to evaluate their match formula: equity, efficiency, and cost. Recognizing that plan sponsors have different objectives and constraints, we offer the criteria to help sponsors make the tradeoffs in plan design explicit and help them meet their goals.
In two-thirds of plans, employer contributions exacerbate pay inequity. Employer contributions are highly concentrated, with 44% of dollars accruing to the top 20% of earners. Many common formulas, including safe harbor designs, disproportionately benefit higher-income employees. An employer match is efficient if it encourages workers to save more. Employee saving rates vary little across plans with different levels of employer matches. The majority (59%) of employer contributions accrue to the 41 % of employees who save more than the match cap, suggesting they would have saved just as much without the match.
Employer contribution costs vary widely. No single formula is a clear winner in terms of efficiency, but dollar caps are more equitable and contain costs. Nonelective contributions that decouple employer contributions from employee choices can also be designed to achieve equity objectives.
Policymakers could do more to promote equity. Adopting additional safe harbor standards with equity considerations could nudge plans toward more equitable designs.
with Adam Bee, Joshua Mitchell, Nikolas Mittag, Jonathan Rothbaum, Carl Sanders, and Matthew Unrath.
Accurately measuring household income and poverty is essential to understanding the nation’s overall economic wellbeing. Many studies show that measurement error stemming from unit nonresponse, item nonresponse and misreporting biases key official statistics such as mean or median income and the official poverty rate. The direction of bias differs between these sources of measurement error. Since these error components are typically studied in isolation, their overall impact on the accuracy of survey estimates remains unclear. This paper summarizes the National Experimental Wellbeing Statistics (NEWS) Project, which integrates this research and address each of these sources of bias simultaneously in order to produce more accurate estimates of household income and poverty. The NEWS project makes three unique contributions. First, we address as many sources of measurement error as we can simultaneously – including unit and item nonresponse and underreporting in surveys as well as the various challenges in administrative data such as measurement error, conceptual misalignment, and incomplete coverage. Second, we bring together all of the available survey and administrative data, which allows to address many of the shortcomings of individual data sources. Third, we propose a model to combine survey and administrative earnings data given measurement error in both sources, replacing ad hoc assumptions that have been used in prior work.
All Working Papers
with Menaka Hampole, Dimitris Papanikolaou, and Bryan Seegmiller, Revise and Resubmit at the Quarterly Journal of Economics. Updated July 2025
We use advances in natural language processing to construct new measures of workers’ task-level exposure to artificial intelligence (AI) and machine learning from 2010 to 2023, capturing variation across firms, occupations, and time. Tasks with higher AI exposure subsequently experience reduced labor demand. To interpret these patterns, we develop a model that separates direct substitution from indirect reallocative effects of labor-saving technologies. Two variables summarize the impact of AI on within-firm labor demand: the mean exposure of an occupation’s tasks, which depresses demand, and the concentration of exposure in a few tasks, which offsets losses by enabling workers to reallocate effort. Using an instrument based on historical university hiring networks, we find causal evidence consistent with these predictions. Despite strong substitution at the task level, overall employment effects are modest, as reduced demand in exposed occupations is offset by productivity-driven increases in labor demand at AI-adopting firms.
with Leonid Kogan, Dimitris Papanikolaou, and Bryan Seegmiller. Revise and Resubmit at the Review of Economic Studies. Updated July 2024
We develop measures of labor-saving and labor-augmenting technology exposure using textual analysis of patents and job tasks. Using US administrative data, we show that exposure to labor-saving technologies negatively affects the earnings of exposed workers. This negative effect is pervasive across both blue- and white-collar workers and across workers of different ages or earnings relative to their peers. In contrast, labor-augmenting technologies have a heterogeneous impact on exposed workers. While the wage bill paid to affected groups rises, this increase is driven primarily by an increase in employment, while earnings rise for new entrants but decline for incumbent workers. This decline is primarily present among white-collar, older, and higher-paid workers, highlighting the importance of vintage-specific human capital. Last, we find positive spillovers of both types of innovation at the industry level, benefiting other workers in the same industry who are not directly exposed to these innovations.
with Brice Green, Leonid Kogan, and Dimitris Papanikolaou, Last Updated December 2025
Using U.S. administrative data, we find that technology-driven creative destruction in the product market passes through to worker earnings. The passthrough to incumbent worker earnings is both asymmetric and concentrated: profit drops from rival innovations lead to proportionally greater earning declines and changes in the likelihood of job destruction than profit gains from their own firm's innovations, while top workers are significantly more exposed than the average worker. We develop an endogenous-growth model with monopsonistic labor markets and worker heterogeneity that replicates this asymmetry and the distribution of earnings risk. Creative destruction exposes high-income workers to concentrated downside risk while offering lower-income workers upward mobility, shaping the welfare consequences of innovation policy.
Note: This paper builds on and subsumes previous work in an earlier paper, entitled Technological Innovation and Labor Income Risk, which was joint work with Leonid Kogan, Dimitris Papanikolaou, and Jae Song
with Sung Je Byun and Johnathan Loudis, Revise and Resubmit at the Journal of Financial Economics, Updated December 2025
We construct a Broad Market Factor (BMF), which is a proxy for the value-weighted equity return on all firms in the US economy (public and private). The BMF differs from the standard Value-weighted Market Factor (VMF), which reflects the value-weighted equity return on public firms. We define the difference between the VMF and the BMF to be the Idiosyncratic Financial Factor (IFF). The IFF carries no risk premium and is uncorrelated with all macroeconomic proxies for investor marginal utility we consider. CAPM betas and, consequently, discount rates are underestimated when measured with respect to the VMF compared to the BMF for most portfolios. Size factors become redundant and the size anomaly is resolved when the VMF is replaced by the BMF in standard factor models. The intertemporal risk-return relation is substantially stronger when one replaces the VMF with the BMF. The unifying explanation for these results is that the IFF adds unpriced risk to the VMF, distorting both cross-sectional and time-series estimates of exposure to priced market risk.
with J. Carter Braxton, Kyle Herkenhoff, Chengdai Huang, Michael Nattinger, and Jonathan Rothbaum
We estimate the evolution of permanent and transitory income risk across the income distribution and over time using newly-digitized and longitudinally-linked Census-IRS tax returns. Since the 1970s, the variance of permanent income shocks (i.e., permanent income risk) has increased by over 65% for those in the top 5% of the income distribution. Using capitalized interest and dividend income, we document that high income households save significantly more in response to increases in permanent income risk compared to lower income households. To examine the implications of rising permanent income risk among high income households we integrate our income process into a Bewley-Huggett-Aiyagari model and calibrate the model to be consistent with our savings elasticities. We find that increasing permanent income risk among high income households has put downward pressure on interest rates and increased wealth inequality.
with Janet Gao, Shan Ge, and Cristina Tello-Trillo, Revise and Resubmit at the Review of Financial Studies.
Employer-sponsored health insurance is a significant component of labor costs. We examine how insurance premiums causally affect worker outcomes across the income distribution. For identification, we instrument premiums using idiosyncratic variation in insurers' recent losses. Analyzing US administrative data, we find that higher premiums adversely affect low-income workers but not high-income workers. Following premium increases, low-income workers face higher rates of job separation, unemployment, large earnings losses, and transitions to staffing arrangements, as well as lower wage growth even when retained. In contrast, high-income workers experience minimal adverse effects and even benefit on some dimensions.
with Yinchu Zhu, Walter P. Heller Memorial Award Winner. Updated June 2025
We propose a simple alternative to linear-in-parameters quantile regressions for modeling conditional distributions. Our approach parameterizes the conditional quantile function using a single “location” quantile (typically the median), with other quantiles constructed by adding or subtracting sums of exponentially affine functions—quantile spacings. This generalized location-scale specification preserves the computational tractability of linear quantile regression, avoids quantile crossing, and imposes a scale restriction motivated by a changes-in-changes model (Athey and Imbens, 2006). The method integrates easily with other econometric frameworks, including instrumental variable models, machine learning, quantile factor models, and nonlinear synthetic controls. We illustrate the approach using U.S. employer–employee matched data to study the effects of mass layoffs on the earnings distribution of displaced workers. We find that average effects—consistent with prior literature—mask a substantial thickening of the left tail, especially during downturns. These findings highlight large welfare costs that are not captured by changes in mean earnings alone.
with Fiona Greig, Anna Madamba, Guillermo Carranza, Cormac O'Dea, Taha Choukhmane, May 2024
We propose criteria that employers can use to evaluate their match formula: equity, efficiency, and cost. Recognizing that plan sponsors have different objectives and constraints, we offer the criteria to help sponsors make the tradeoffs in plan design explicit and help them meet their goals.
In two-thirds of plans, employer contributions exacerbate pay inequity. Employer contributions are highly concentrated, with 44% of dollars accruing to the top 20% of earners. Many common formulas, including safe harbor designs, disproportionately benefit higher-income employees. An employer match is efficient if it encourages workers to save more. Employee saving rates vary little across plans with different levels of employer matches. The majority (59%) of employer contributions accrue to the 41 % of employees who save more than the match cap, suggesting they would have saved just as much without the match.
Employer contribution costs vary widely. No single formula is a clear winner in terms of efficiency, but dollar caps are more equitable and contain costs. Nonelective contributions that decouple employer contributions from employee choices can also be designed to achieve equity objectives.
Policymakers could do more to promote equity. Adopting additional safe harbor standards with equity considerations could nudge plans toward more equitable designs.
with Adam Bee, Joshua Mitchell, Nikolas Mittag, Jonathan Rothbaum, Carl Sanders, and Matthew Unrath.
Accurately measuring household income and poverty is essential to understanding the nation’s overall economic wellbeing. Many studies show that measurement error stemming from unit nonresponse, item nonresponse and misreporting biases key official statistics such as mean or median income and the official poverty rate. The direction of bias differs between these sources of measurement error. Since these error components are typically studied in isolation, their overall impact on the accuracy of survey estimates remains unclear. This paper summarizes the National Experimental Wellbeing Statistics (NEWS) Project, which integrates this research and address each of these sources of bias simultaneously in order to produce more accurate estimates of household income and poverty. The NEWS project makes three unique contributions. First, we address as many sources of measurement error as we can simultaneously – including unit and item nonresponse and underreporting in surveys as well as the various challenges in administrative data such as measurement error, conceptual misalignment, and incomplete coverage. Second, we bring together all of the available survey and administrative data, which allows to address many of the shortcomings of individual data sources. Third, we propose a model to combine survey and administrative earnings data given measurement error in both sources, replacing ad hoc assumptions that have been used in prior work.
All Publications
with Maarten Meeuwis, Dimitris Papanikolaou, and Jonathan Rothbaum. Conditionally Accepted at the American Economic Review. Updated October 2025
Using U.S. administrative data on worker earnings, we show that increases in risk premia lead to lower labor earnings, particularly for lower-paid workers. These declines are primarily driven by job separations. We build an equilibrium model of labor market search that quantitatively replicates the observed heterogeneity in labor market dynamics across worker earnings levels. Our findings underscore the role of time-varying risk premia as a key driver of labor market fluctuations and highlight the importance of both the job creation and the job destruction margins in understanding the heterogeneity in worker outcomes over the business cycle.
with Taha Choukhmane, Jorge Colmenares, Cormac O'Dea, and Jonathan Rothbaum. Conditionally accepted at the American Economic Review. Updated October 2025
U.S. employers and the federal government devote the equivalent of 1.5% of GDP annually toward promoting defined contribution (DC) retirement savings. Using a new employer-employee linked dataset covering millions of Americans, we show that tax and employer matching incentives disproportionately benefit White and Asian workers compared to their similar-income Hispanic, Black, and American Indian or Alaska Native coworkers. Similarly, these incentives disproportionately benefit those with richer parents compared to those from lower-income families. Breaking the link between contribution choices and saving subsidies through revenue-neutral reforms could close up to one-third of the DC wealth gaps by race and parental income.
with Carter Braxton, Kyle Herkenhoff, and Jonathan Rothbaum. American Economic Review, December 2025.
For whom has earnings risk changed, and why? We answer these questions by combining the Kalman filter and EM-algorithm to estimate persistent and temporary earnings for every individual at every point in time. We apply our method to administrative earnings linked with survey data. We show that since the 1980s, persistent earnings risk rose by 12.5% for both employed and unemployed workers and the scarring effects of unemployment doubled. At the same time, temporary earnings risk declined. Using education and occupation codes, we show that rising persistent earnings risk is concentrated among high-skill workers and related to technology adoption.
Journal of Financial Economics, October 2025. Winner of 2015 AQR Top Finance Graduate Award and 2015 Cubist Systematic Strategies Ph.D. Candidate Award for Outstanding Research
Administrative earnings data reveal that households are exposed to large, countercyclical idiosyncratic tail risks in labor earnings. I illustrate how these risks affect asset prices within an asset pricing framework with recursive preferences, heterogeneous agents and incomplete markets. Quantitatively, a model in which agents face a time-varying probability of experiencing a rare, idiosyncratic disaster, with parameters disciplined by data, matches the level and dynamics of the equity premium. Stock returns are highly informative about labor market event risk, and, consistent with model predictions, initial claims for unemployment, a proxy for labor market uncertainty, is a highly robust predictor of returns.
with Klakow Akepanidtaworn, Rick Di Mascio, and Alex Imas. Journal of Finance, August 2023. Dimensional Fund Advisors First Prize Award Winner
Are market experts prone to heuristics, and if so, do they transfer across closely related domains---buying and selling? We investigate this question using a unique dataset of institutional investors with portfolios averaging $573 million. A striking finding emerges: while there is clear evidence of skill in buying, selling decisions underperform substantially---even relative to random selling strategies. This holds despite the similarity between the two decisions in frequency, substance and consequences for performance. Evidence suggests that an asymmetric allocation of cognitive resources such as attention can explain the discrepancy: we document a systematic, costly heuristic process when selling but not when buying.
with Leland Farmer and Allan Timmermann, Journal of Finance, April 2023
For many benchmark predictor variables, short-horizon return predictability in the U.S. stock market is local in time as short periods with significant predictability (‘pockets’) are interspersed with long periods with little or no evidence of return predictability. We document this result empirically using a flexible time-varying parameter model which estimates predictive coefficients as a nonparametric function of time and explore possible explanations of this finding, including time-varying risk-premia for which we only find limited support. Conversely, pockets of return predictability are consistent with a sticky expectations model in which investors only slowly update their beliefs about a persistent component in the cash flow process.
Note: A minor coding error impacted some of the results using the original method in the paper. In this note, we show that a simple adjustment to the estimation procedure restores the key results of the published paper.
with Huben Liu, Dimitris Papanikolaou, and Bryan Seegmiller. Forthcoming in the Brookings Papers on Economic Activity, Fall 2025
We use recent advances in natural language processing and large language models to construct novel measures of technology exposure for workers that span almost two centuries. Combining our measures with Census data on occupation employment, we show that technological progress over the 20th century has led to economically meaningful shifts in labor demand across occupations: it has consistently increased demand for occupations with higher education requirements, occupations that pay higher wages, and occupations with a greater fraction of female workers. Using these insights and a calibrated model, we then explore different scenarios for how advances in artificial intelligence (AI) are likely to impact employment trends in the medium run. The model predicts a reversal of past trends, with AI favoring occupations that are lower-educated, lower-paid, and more male-dominated.
with Joel Flynn and Alexis Toda, Theoretical Economics, January 2023
We study a general class of consumption-savings problems with recursive preferences. We characterize the sign of the consumption response to arbitrary shocks in terms of the product of two sufficient statistics: the elasticity of intertemporal substitution between contemporaneous consumption and continuation utility (EIS), and the relative elasticity of the marginal value of wealth (REMV). Under homotheticity, the REMV always equals one, so the propensity of the agent to save or dissave is always signed by the relationship of the EIS with unity. We apply our results to derive comparative statics in classical problems of portfolio allocation, consumption-savings with income risk, and entrepreneurial investment. Our results suggest empirical identification strategies for both the value of the EIS and its relationship with unity.
with Dimitris Papanikolaou and Bryan Seegmiller, Explorations in Economic History, January 2023
We detail a methodology for estimating the textual similarity between two documents while accounting for the possibility that two different words can have a similar meaning. We illustrate the method's usefulness in facilitating comparisons between documents with very different formats and vocabularies by textually linking occupation task and industry output descriptions with related technologies as described in patent texts; we also examine economic applications of the resultant document similarity measures. In a final application we demonstrate that the method also works well relative to alternatives for comparing documents within the same domain by showing that pairwise textual similarity between occupations' task descriptions strongly predicts the probability that a given worker will transition from one occupation to another. Finally, we offer some suggestions on other potential uses and guidance in implementing the method.
with Dimitris Papanikolaou. Review of Asset Pricing Studies, March 2022
We analyze the supply-side disruptions associated with Covid-19 across firms and workers. To do so, we exploit differences in the ability of workers across industries to work remotely using data from the American Time Use Survey (ATUS). We find that sectors in which a higher fraction of the workforce is not able to work remotely experienced significantly greater declines in employment, significantly more reductions in expected revenue growth, worse stock market performance, and higher expected likelihood of default. In terms of individual employment outcomes, lower-paid workers, especially female workers with young children, were significantly more affected by these disruptions. Last, we combine these ex-ante heterogeneous industry exposures with daily financial market data to create a stock return portfolio that most closely replicates the supply-side disruptions resulting from the pandemic.
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with Emily Gallagher, Allan Timmermann, and Russ Wermers, Review of Financial Studies, April 2020
We study investor redemptions and portfolio rebalancing decisions of prime money market mutual funds (MMFs) during the Eurozone crisis. We find evidence that investors selectively acquire and act upon information about MMFs' risk exposures. In turn, this provides strong incentives for managers to withdraw funding from issuers whose debt becomes information-sensitive. Consistent with this, we show that MMF managers, particularly those serving the most sophisticated investors, selectively adjust their portfolio risk exposures to avoid information-sensitive European risks, while maintaining or increasing risk exposures to other regions. This mechanism helps to explain the occurrence of selective dry-ups in debt markets where delegation is common and returns to information production are often low.
with Allan Timmermann and Russ Wermers, American Economic Review, September 2016
We study daily money market mutual fund flows at the individual share class level during September 2008. This fine granularity of data facilitates new insights into investor and portfolio holding characteristics conducive to run risk in cash-like asset pools. Empirically, we find that cross-sectional flow data observed during the week of the Lehman failure are consistent with key implications of a simple model of coordination with incomplete information and strategic complementarities. Similar conclusions follow from daily models fitted to capture dynamic interactions between investors with differing levels of sophistication within the same money fund, holding constant the underlying portfolio.
with Brendan Beare, Journal of Applied Econometrics, March 2016
A large class of asset pricing models predicts that securities which have high payoffs when market returns are low tend to be more valuable than those with high payoffs when market returns are high. More generally, we expect the projection of the stochastic discount factor on the market portfolio--that is, the discounted pricing kernel evaluated at the market portfolio--to be a monotonically decreasing function of the market portfolio. Numerous recent empirical studies appear to contradict this prediction. The nonmonotonicity of empirical pricing kernel estimates has become known as the pricing kernel puzzle. In this paper we propose and apply a formal statistical test of pricing kernel monotonicity. We apply the test using seventeen years of data from the market for European put and call options written on the S&P 500 index. Statistically significant violations of pricing kernel monotonicity occur in a substantial proportion of months, suggesting that observed nonmonotonicities are unlikely to be the product of statistical noise.
Journal of Mathematical Economics, January 2012
The Shapley-Folkman Theorem places a scalar upper bound on the distance between a sum of non-convex sets and its convex hull. We observe that some information is lost when a vector is converted to a scalar to generate this bound and propose a simple normalization of the underlying space which removes this loss of information. As an example, we apply this result to the Anderson (1978) core convergence theorem, and demonstrate how our normalization leads to an intuitive, unitless upper bound on the discrepancy between an arbitrary core allocation and the corresponding competitive equilibrium allocation.
All Publications
with Maarten Meeuwis, Dimitris Papanikolaou, and Jonathan Rothbaum. Conditionally Accepted at the American Economic Review. Updated October 2025
Using U.S. administrative data on worker earnings, we show that increases in risk premia lead to lower labor earnings, particularly for lower-paid workers. These declines are primarily driven by job separations. We build an equilibrium model of labor market search that quantitatively replicates the observed heterogeneity in labor market dynamics across worker earnings levels. Our findings underscore the role of time-varying risk premia as a key driver of labor market fluctuations and highlight the importance of both the job creation and the job destruction margins in understanding the heterogeneity in worker outcomes over the business cycle.
with Taha Choukhmane, Jorge Colmenares, Cormac O'Dea, and Jonathan Rothbaum. Conditionally accepted at the American Economic Review. Updated October 2025
U.S. employers and the federal government devote the equivalent of 1.5% of GDP annually toward promoting defined contribution (DC) retirement savings. Using a new employer-employee linked dataset covering millions of Americans, we show that tax and employer matching incentives disproportionately benefit White and Asian workers compared to their similar-income Hispanic, Black, and American Indian or Alaska Native coworkers. Similarly, these incentives disproportionately benefit those with richer parents compared to those from lower-income families. Breaking the link between contribution choices and saving subsidies through revenue-neutral reforms could close up to one-third of the DC wealth gaps by race and parental income.
with Carter Braxton, Kyle Herkenhoff, and Jonathan Rothbaum. American Economic Review, December 2025.
For whom has earnings risk changed, and why? We answer these questions by combining the Kalman filter and EM-algorithm to estimate persistent and temporary earnings for every individual at every point in time. We apply our method to administrative earnings linked with survey data. We show that since the 1980s, persistent earnings risk rose by 12.5% for both employed and unemployed workers and the scarring effects of unemployment doubled. At the same time, temporary earnings risk declined. Using education and occupation codes, we show that rising persistent earnings risk is concentrated among high-skill workers and related to technology adoption.
Journal of Financial Economics, October 2025. Winner of 2015 AQR Top Finance Graduate Award and 2015 Cubist Systematic Strategies Ph.D. Candidate Award for Outstanding Research
Administrative earnings data reveal that households are exposed to large, countercyclical idiosyncratic tail risks in labor earnings. I illustrate how these risks affect asset prices within an asset pricing framework with recursive preferences, heterogeneous agents and incomplete markets. Quantitatively, a model in which agents face a time-varying probability of experiencing a rare, idiosyncratic disaster, with parameters disciplined by data, matches the level and dynamics of the equity premium. Stock returns are highly informative about labor market event risk, and, consistent with model predictions, initial claims for unemployment, a proxy for labor market uncertainty, is a highly robust predictor of returns.
with Klakow Akepanidtaworn, Rick Di Mascio, and Alex Imas. Journal of Finance, August 2023. Dimensional Fund Advisors First Prize Award Winner
Are market experts prone to heuristics, and if so, do they transfer across closely related domains---buying and selling? We investigate this question using a unique dataset of institutional investors with portfolios averaging $573 million. A striking finding emerges: while there is clear evidence of skill in buying, selling decisions underperform substantially---even relative to random selling strategies. This holds despite the similarity between the two decisions in frequency, substance and consequences for performance. Evidence suggests that an asymmetric allocation of cognitive resources such as attention can explain the discrepancy: we document a systematic, costly heuristic process when selling but not when buying.
with Leland Farmer and Allan Timmermann, Journal of Finance, April 2023
For many benchmark predictor variables, short-horizon return predictability in the U.S. stock market is local in time as short periods with significant predictability (‘pockets’) are interspersed with long periods with little or no evidence of return predictability. We document this result empirically using a flexible time-varying parameter model which estimates predictive coefficients as a nonparametric function of time and explore possible explanations of this finding, including time-varying risk-premia for which we only find limited support. Conversely, pockets of return predictability are consistent with a sticky expectations model in which investors only slowly update their beliefs about a persistent component in the cash flow process.
Note: A minor coding error impacted some of the results using the original method in the paper. In this note, we show that a simple adjustment to the estimation procedure restores the key results of the published paper.
with Huben Liu, Dimitris Papanikolaou, and Bryan Seegmiller. Forthcoming in the Brookings Papers on Economic Activity, Fall 2025
We use recent advances in natural language processing and large language models to construct novel measures of technology exposure for workers that span almost two centuries. Combining our measures with Census data on occupation employment, we show that technological progress over the 20th century has led to economically meaningful shifts in labor demand across occupations: it has consistently increased demand for occupations with higher education requirements, occupations that pay higher wages, and occupations with a greater fraction of female workers. Using these insights and a calibrated model, we then explore different scenarios for how advances in artificial intelligence (AI) are likely to impact employment trends in the medium run. The model predicts a reversal of past trends, with AI favoring occupations that are lower-educated, lower-paid, and more male-dominated.
with Joel Flynn and Alexis Toda, Theoretical Economics, January 2023
We study a general class of consumption-savings problems with recursive preferences. We characterize the sign of the consumption response to arbitrary shocks in terms of the product of two sufficient statistics: the elasticity of intertemporal substitution between contemporaneous consumption and continuation utility (EIS), and the relative elasticity of the marginal value of wealth (REMV). Under homotheticity, the REMV always equals one, so the propensity of the agent to save or dissave is always signed by the relationship of the EIS with unity. We apply our results to derive comparative statics in classical problems of portfolio allocation, consumption-savings with income risk, and entrepreneurial investment. Our results suggest empirical identification strategies for both the value of the EIS and its relationship with unity.
with Dimitris Papanikolaou and Bryan Seegmiller, Explorations in Economic History, January 2023
We detail a methodology for estimating the textual similarity between two documents while accounting for the possibility that two different words can have a similar meaning. We illustrate the method's usefulness in facilitating comparisons between documents with very different formats and vocabularies by textually linking occupation task and industry output descriptions with related technologies as described in patent texts; we also examine economic applications of the resultant document similarity measures. In a final application we demonstrate that the method also works well relative to alternatives for comparing documents within the same domain by showing that pairwise textual similarity between occupations' task descriptions strongly predicts the probability that a given worker will transition from one occupation to another. Finally, we offer some suggestions on other potential uses and guidance in implementing the method.
with Dimitris Papanikolaou. Review of Asset Pricing Studies, March 2022
We analyze the supply-side disruptions associated with Covid-19 across firms and workers. To do so, we exploit differences in the ability of workers across industries to work remotely using data from the American Time Use Survey (ATUS). We find that sectors in which a higher fraction of the workforce is not able to work remotely experienced significantly greater declines in employment, significantly more reductions in expected revenue growth, worse stock market performance, and higher expected likelihood of default. In terms of individual employment outcomes, lower-paid workers, especially female workers with young children, were significantly more affected by these disruptions. Last, we combine these ex-ante heterogeneous industry exposures with daily financial market data to create a stock return portfolio that most closely replicates the supply-side disruptions resulting from the pandemic.
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with Emily Gallagher, Allan Timmermann, and Russ Wermers, Review of Financial Studies, April 2020
We study investor redemptions and portfolio rebalancing decisions of prime money market mutual funds (MMFs) during the Eurozone crisis. We find evidence that investors selectively acquire and act upon information about MMFs' risk exposures. In turn, this provides strong incentives for managers to withdraw funding from issuers whose debt becomes information-sensitive. Consistent with this, we show that MMF managers, particularly those serving the most sophisticated investors, selectively adjust their portfolio risk exposures to avoid information-sensitive European risks, while maintaining or increasing risk exposures to other regions. This mechanism helps to explain the occurrence of selective dry-ups in debt markets where delegation is common and returns to information production are often low.
with Allan Timmermann and Russ Wermers, American Economic Review, September 2016
We study daily money market mutual fund flows at the individual share class level during September 2008. This fine granularity of data facilitates new insights into investor and portfolio holding characteristics conducive to run risk in cash-like asset pools. Empirically, we find that cross-sectional flow data observed during the week of the Lehman failure are consistent with key implications of a simple model of coordination with incomplete information and strategic complementarities. Similar conclusions follow from daily models fitted to capture dynamic interactions between investors with differing levels of sophistication within the same money fund, holding constant the underlying portfolio.
with Brendan Beare, Journal of Applied Econometrics, March 2016
A large class of asset pricing models predicts that securities which have high payoffs when market returns are low tend to be more valuable than those with high payoffs when market returns are high. More generally, we expect the projection of the stochastic discount factor on the market portfolio--that is, the discounted pricing kernel evaluated at the market portfolio--to be a monotonically decreasing function of the market portfolio. Numerous recent empirical studies appear to contradict this prediction. The nonmonotonicity of empirical pricing kernel estimates has become known as the pricing kernel puzzle. In this paper we propose and apply a formal statistical test of pricing kernel monotonicity. We apply the test using seventeen years of data from the market for European put and call options written on the S&P 500 index. Statistically significant violations of pricing kernel monotonicity occur in a substantial proportion of months, suggesting that observed nonmonotonicities are unlikely to be the product of statistical noise.
Journal of Mathematical Economics, January 2012
The Shapley-Folkman Theorem places a scalar upper bound on the distance between a sum of non-convex sets and its convex hull. We observe that some information is lost when a vector is converted to a scalar to generate this bound and propose a simple normalization of the underlying space which removes this loss of information. As an example, we apply this result to the Anderson (1978) core convergence theorem, and demonstrate how our normalization leads to an intuitive, unitless upper bound on the discrepancy between an arbitrary core allocation and the corresponding competitive equilibrium allocation.




