We present an empirical study of stress testing for portfolios of auto loans. We find that loans aged five years or more have significantly higher default probabilities. This finding raises concerns about the increasing maturity of auto loans in recent years. A challenge in stress testing is the instability of the estimated coefficient of macroeconomic variables, which raises questions on the reliability of stress test results. For this reason, it is important for model developers to perform sensitivity analyses and make conservative adjustment to minimize model risk.

We use an investment-based asset pricing model to examine the effect of firms’ investments relative to cash holdings on stock returns, assuming holding cash lowers transaction costs. We find that mimicking portfolios based on investments relative to non-cash capital and based on investments relative to cash capital are priced for various testing portfolios. On average, momentum stocks and growth stocks are more sensitive to the factor constructed using investment relative to cash.

The entry of High-Speed Railways (HSR) represents disruptive competition to airlines. Utilizing a unique dataset of all flights departing from Beijing to 113 domestic destinations in China since January 2009, we employ a difference-in-differences approach to examine the effects of HSR entry on on-time performance and to identify the channels. We document two main findings. First, the entry of HSR leads to significant reductions in the mean and variance of travel delays on the affected airline routes. Second, the reductions in departure delays and taxi-in times at the destination airports are identified as the main channels.

We apply machine learning methods to granular environmental variables and test if there is a strong positive relation between environmental sustainability and future stock returns. A long-short portfolio that longs stocks with high forecasted returns and sells stocks with low forecasted returns earns large abnormal returns, and it performs better when climate concerns in the media are more intense. Further diagnosis shows that various dimensions of environmental sustainability help return predictions. High forecasted returns are associated primarily with strong environmental operational performance. The return prediction based on a customized transformer model is similar.