This paper develops methodology for semiparametric panel data models in a setting where both the time series and the cross section are large. Such set tings are common in finance and other areas of economics. Our model allows for heterogeneous nonparametric covariate effects as well as...

This paper uses proprietary data to evaluate the efficacy of single-stock circuit breakers on the London Stock Exchange during July and August 2011. We exploit exogenous variation in the length of the uncrossing periods that follow a trading suspension to estimate the effect of auction length on...