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Xi Wu Publications

Publish Date
Working Paper
Abstract

The European Union Emission Trading System is a prominent market-based mechanism to reduce emissions. While the theory is well-understood, we are the first to study the whole cap-and-trade mechanism as a financial market. Analyzing the universe of transactions in 2005-2020 (more than one million records of granular transaction data), we show that this market features significant inefficiencies undermining its goals. First, about 40% of firms never trade in a given year. Second, many firms only trade during surrendering months, when compliance is immediate and prices are predictably high. Third, a number of operators engage in speculative trading, exploiting private information.

Working Paper
Abstract

Analyzing the universe of federal environmental regulations in the U.S., we construct a measure of regulations—direct taxes on pollution. Analyzing the universe of firms’ investor disclosures, we construct a measure of material environmental concerns—indirect taxes on pollution. These two empirical measures are new to the environmental regulations literature. Thirdly, we document an important new fact that the cross-sectional distribution of pollution changes is lumpy. We build a dynamic heterogeneous firm model with non-convex adjustment costs that fits the cross-sectional pollution evidence. The model explains half of the pollution decline in U.S. manufacturing over the last two decades due to direct and indirect taxes. We show that the dynamics of direct taxes (environmental regulations) and indirect taxes (environmental concerns), non-convex adjustment costs, and idiosyncratic productivity shocks are key determinants of pollution dynamics in U.S. manufacturing.

Working Paper
Abstract

We empirically and quantitatively study the impact of supply chain disruptions on U.S. businesses. Leveraging granular shipment-level data on the universe of U.S. seaborne imports with nearly 200 million observations, we construct a measure of disruptions at the individual firm level for the time period 2013-2023. We document a significant heterogeneity in disruption rates among U.S. public firms, with a notable increase observed in recent years. We introduce a notion of supplier capital and investigate the effect of supply disruptions on firms’ investment decisions. In the data, firms tend to increase investment in supplier capital following the shock, however, financially distressed firms exhibit a much weaker response. We develop a general equilibrium model with heterogeneous firms and with investment in supplier capital. We show that firms’ ability to accumulate supplier capital by making costly investment is an important margin of adjustment in the aftermath of such crises. Financial constraints help account for the heterogeneous treatment effect observed in the data. Two supply chain initiatives proposed by the U.S. government to mitigate disruptions are evaluated. Finally, we document a significant rise in supply disruptions in sectors critical to the U.S. economy and build an index of critical supply disruptions. We show quantitatively that firms relying heavily on imports of critical products experience a much larger decline in output following a disruption shock relative to firms which are not engaged in critical supply chains.

Journal of Finance
Abstract

We find that three factors – cryptocurrency market, size, and momentum – capture the cross-sectional expected cryptocurrency returns. We consider a comprehensive list of price- and market-related return predictors in the stock market, and construct their cryptocurrency counterparts. Ten cryptocurrency characteristics form successful long-short strategies that generate sizable and statistically significant excess returns, and we show that all of these strategies are accounted for by the cryptocurrency three-factor model. Lastly, we examine potential underlying mechanisms of the cryptocurrency size and momentum effects.