Do Interest Rates Follow Unit-Root Processes? Evidence from Cross-Maturity Treasury Bill Yields

Abstract. It is widely reported in the literature that interest rates follow integrated processes. Many empirical studies have, in fact, taken this result as a maintained hypothesis. This article demonstrates that the failure to reject the hypothesis that interest rates contain a unit root may be due to the severe power problem of standard test procedures in small samples. We analyze a panel of cross-maturity Treasury-bill yield series by employing a panel-based test. This test exploits cross-maturity variations of the data to improve estimation efficiency and is more powerful than standard tests for unit roots. The critical values of the test statistics are computed by Monte Carlo simulations tailored to our samples. It is found that the null hypothesis that each yield series contains a unit root can be decisively rejected. Our findings cast some doubt on previous studies that rely on the nonstationarity assumption of interest rates.     

Heterogeneous Background Risks and Portfolio Choice: Evidence from Micro‐level Data

We construct a set of household‐level background risk variables to capture the covariance structure of three nonfinancial assets and two financial assets. These risks are in general statistically significant and economically important for a household's stock market participation and stockholdings. A one‐standard‐deviation increase in background risks reduces the participation probability by 11% and the stockholdings‐to‐wealth ratio by 4%. The volatilities of labor income, housing value, and business income reduce a household's participation and stockholdings. A household with labor income highly correlated with stock (bond) returns is less (more) likely to invest in stock.