In this paper we investigate portfolio coskewness using a quadratic market model as return generating process. It is shown that portfolios of small (large) firms have negative (positive) coskewness with market. An asset pricing model including coskewness is tested through the restrictions it...

In this paper it is shown that "classical" tests can become asymptotically inadmissible (i.e. we show that there exist uniformly better tests) if the information matrix becomes stochastic: A typical example is the augmented Dickey-Fuller test for unit roots (in case of no deterministic trend. We...

The notion of cointegration was developed by Engle and Granger (1987), and since then has been considered important in the recent development of time series econometrics. Many statistical methods have been developed for the analysis of the cointegrated systems, and several methods of estimating...

Existing methods for constructing confidence bands for multivariate impulse response functions depend on auxiliary assumptions on the order of integration of the variables. Thus, they may have poor coverage at long lead times when variables are highly persistent. Solutions that have been...

This paper analyzes the robustness of the estimate of a positive productivity shock on hours to the presence of a possible unit root in hours. Estimations in levels or in first differences provide opposite conclusions. We rely on an agnostic procedure in which the researcher does not have to...

The paper introduces a novel approach to testing for unit roots in panels. Following Chang and Park (2004), the approach takes a new contour that is drawn along the line given by the equi-squared-sum instead of the traditional one given by the equi-sample-size. As we show in the paper, the...

This paper develops a limiting theory for Wald tests of weak exogeneity in error correction models (ECMs). It is well known that Wald statistics on cointegrated systems may involve nonstandard distribution and nuisance parameters, if $I(1)$ variables are not negligible in the statistics. To...

The aim of the paper is to fulfill the gap for testing hypotheses on parameters of the log-normal stochastic volatility model, more precisely, to propose finite sample exact tests in the sense that the tests have correct levels in small samples. To do this, we examine method-of-moments-based...