Published Papers

We review an empirical literature that studies how political polarization affects financial decisions. We first discuss the degree of partisan segregation in finance and corporate America, the mechanisms through which partisanship may influence financial decisions, and available data sources to infer individuals' partisan leanings. We then describe and discuss the empirical evidence. Our review suggests an economically large and often growing partisan gap in the financial decisions of households, corporate executives, and financial intermediaries. Partisan alignment between individuals explains team and financial relationship formation, with initial evidence suggesting that high levels of partisan homogeneity may be associated with economic costs. We conclude by proposing several promising directions for future research.

This paper examines how beliefs and preferences drive identity-conforming consumption or investments. We introduce a theory that explains how identity distorts individuals' beliefs about potential outcomes and imposes psychic costs on benefiting from identity- incongruent sources. We substantiate our theoretical foundation through two lab-in- field experiments on soccer betting in Kenya and the UK, where participants either had established affiliations with the teams involved or assumed a neutral stance. The results indicate that soccer fans have overoptimistic beliefs about match outcomes that align with their identity and bet significantly higher amounts on those than on outcomes of comparable games where they are neutral. After accounting for individuals' beliefs and risk preferences, our structural estimates reveal that participants undervalue gains from identity-incongruent assets by 9% to 27%. Our counterfactual simulations imply that identity-specific beliefs account for 30% to 44% of the investment differences between neutral observers and supporters, with the remainder being due to identity preferences.

We investigate the impact of peer interaction on the quality of financial decision making in a laboratory experiment. Face-to-face communication with a randomly assigned peer significantly improves the quality of subsequent private decisions even though simple mimicry would have the opposite effect. We present evidence that the mechanism involves general conceptual learning (because the benefits of communication extend to previously unseen tasks), and that the most effective learning relationships are horizontal rather than vertical (because people with weak skills benefit most when their partners also have weak skills). The benefits of demonstrably effective financial education do not propagate to peers.

We examine the contagion of investment ideas in a multiperiod setting in which investors are more likely to transmit their ideas to other investors after experiencing higher payoffs in one of two investment styles with different return distributions. We show that heterogeneous investment styles are able to coexist in the long run, implying a greater diversity than predicted by traditional theory. We characterize the survival and popularity of styles in relation to the distribution of security returns. In addition, we demonstrate that psychological effects such as conformist preference can lead to oscillations and bubbles in the choice of style. These results remain robust under a wide class of replication rules and endogenous returns. They offer empirically testable predictions, and provide new insights into the persistence of the wide range of investment strategies used by individual investors, hedge funds, and other professional portfolio managers.

After the run on Silicon Valley Bank (SVB) in March 2023, U.S. regional banks entered a period of significant distress. We quantify social media's role in this distress using comprehensive Twitter data. During the SVB run period, banks with high pre-existing exposure to Twitter lost 4.3 percentage points more stock market value. Moreover, Twitter pre-exposure interacts significantly with classical run risks to predict greater run severity and greater deposit outflows during Q1-2023, effects unexplained by other banking or market characteristics. At the hourly frequency during the run, high Twitter attention over the past four hours predicts stock market losses, especially for banks with high run risks. By contrast, we find that negative Twitter sentiment does not amplify bank run risks. Rather, our evidence points to a distinctive role of Twitter attention, particularly when tweets are retweeted broadly.

We study the nature and effects of cultural biases in choice under risk and uncertainty by comparing peer-to-peer loans the same individuals (lenders) make alone and after observing robo-advised suggestions. When unassisted, lenders are more likely to choose co-ethnic borrowers, facing 8% higher defaults and 7.3pp lower returns. Robo-advising does not affect diversification but reduces lending to high-risk co-ethnic borrowers. Lenders in locations with high inter-ethnic animus drive the results, even when borrowers reside elsewhere. Biased beliefs explain these results better than a conscious taste for discrimination: lenders barely override robo-advised matches to ethnicities they discriminated against when unassisted.

We find evidence of selective exposure to confirmatory information among 400,000 users on the investor social network StockTwits. Self-described bulls are five times more likely to follow a user with a bullish view of the same stock than are self-described bears. Consequently, bulls see 62 more bullish messages and 24 fewer bearish messages than bears do over the same 50-day period. These "echo chambers" exist even among professional investors and are strongest for investors who trade on their beliefs. Finally, beliefs formed in echo chambers are associated with lower ex post returns, more siloing of information, and more trading volume.

In this article, we examine whether comovement in the stock prices of pairs of Chinese firms connected to the same political network are systematically shaped by the prevailing coordination versus competition incentives of that network's politicians. We find strong evidence from 2000 to 2012 (Jiang's and Hu's regimes) that stock price comovement is affected by the embeddedness of the firm-politician ties within the network. Among pairs of firms connected to a network through a common politician, we document an increase in stock price comovement. For those pairs of firms connected to a common network via separate politicians (rather than a common politician), we document a relative decrease in stock price comovement. This negative effect suggests that politicians' relationships within these political networks are generally adversarial rather than cooperative in nature. These results become significantly weaker during Xi's regime from 2013 to 2017, suggesting that Xi's anti-corruption campaign and state-owned enterprise reforms may have attenuated these political network effects on the firms. Our additional tests also show that stock price comovement becomes even more positive (negative) in settings which are expected to increase the coordination or decrease the competition (decrease the coordination or increase the competition) of the politicians.

Using hand-collected data spanning more than a decade on European banks' sovereign debt portfolios, we show that the trust of residents of a bank's countries of operation in the residents of a potential target country of investment has a positive, statistically significant, and economically important association with its cross-border exposures. In identifying cultural stereotypes at the bank level, we show that corporate culture at bank headquarters is influenced by foreign subsidiaries for several reasons, including banks' tendency to hire internally across borders for high-level managerial positions. We therefore leverage the geography of multinational bank branch networks to construct a bank-specific measure of culture that differs across banks headquartered in the same country, at the same point in time, with regard to the same target country. This allows us to compare how sovereign exposures are affected by cultural stereotypes while ruling out confounding factors at country and country-pair levels. The effect of stereotypes is persistent overtime, stronger for less diversified banks, and weaker for target countries whose bonds appear more frequently in bank portfolios. Cultural stereotypes are particularly salient when governments are hit by sovereign debt crises.

Using machine learning-based algorithms, we measure key impressions about sell-side analysts using their LinkedIn photos. We find that impressions of analysts' trustworthiness (TRUST) and dominance (DOM) are positively associated with forecast accuracy, especially after recent in-person meetings between analysts and firm managers. High TRUST also enhances stock return sensitivity to forecast revisions, especially for stocks with high institutional ownership. In contrast, the impression of analysts' attractiveness (ATTRACT) is only positively associated with accuracy for new analysts or when a firm has a new CEO or CFO. Furthermore, while high DOM helps male analysts' chances of attaining All-Star status, it reduces female analysts' accuracy and the likelihood of winning the All-Star award. In addition, the relation between TRUST and accuracy is modulated by the disclosure environment and is attenuated by Regulation Fair Disclosure. Our results suggest that face impressions influence analysts' access to information and the perceived credibility of their reports.

We analyze the partisanship of Commissioners at the SEC and Governors at the Federal Reserve Board. Using recent advances in machine learning, we identify partisan phrases in Congress, such as "red tape" and "climate change," and observe their usage among regulators. Although the Fed has remained relatively nonpartisan throughout our sample period (1930-2019), we find that partisanship among SEC Commissioners rose to an all-time high during the 2010-2019 period, driven by more-partisan Commissioners replacing less-partisan ones. Partisanship at the SEC appears in both the language of new SEC rules and the voting behavior of SEC Commissioners.

Maintaining economic output during the COVID-19 pandemic results in benefits for firm shareholders but comes at a potential cost to public health. Using store-level data, we examine how a CEO's political leaning impacts this trade-off. We document that firms with a Republican-leaning CEO experience a relative increase in store visits compared to firms with a Democratic-leaning CEO. The increase in store visits is associated with higher sales and positive abnormal stock returns. However, we also document higher COVID-19 transmission rates and more employee safety complaints in communities where establishments with higher store traffic are managed by a Republican-leaning CEO.