Random subspace methods are a novel approach to obtain accurate forecasts in high-dimensional regression settings. We provide a theoretical justification of the use of random subspace methods and show their usefulness when forecasting monthly macroeconomic variables. We focus on two approaches....

We investigate covariance matrix estimation in vast-dimensional spaces of 1,500 up to 2,000 stocks using fundamental factor models (FFMs). FFMs are the typical benchmark in the asset management industry and depart from the usual statistical factor models and the factor models with observed...

We develop a vector autoregressive model with time variation in the mean and the variance. The unobserved time-varying mean is assumed to follow a random walk and we also link it to long-term Consensus forecasts, similar in spirit to so called democratic priors. The changes in variance are...

This note discusses some aspects of the paper by Hu and Tsay (2014), "Principal Volatility Component Analysis". The key issues are considered, and are also related to existing conditional covariance and correlation models. Some caveats are given about multivariate models of time-varying...

We develop an algorithm that incorporates network information into regression settings. It simultaneously estimates the covariate coefficients and the signs of the network connections (i.e. whether the connections are of an activating or of a repressing type). For the coefficient estimation...

One of the fastest growing areas in empirical finance, and also one of the least rigorously analyzed, especially from a financial econometrics perspective, is the econometric analysis of financial derivatives, which are typically complicated and difficult to analyze. The purpose of this special...

We analyze a market where firms compete in a conventional and an electronicretail channel. Consumers easily compare prices online, but some incur purchaseuncertainties on the online channel. We investigate the market shares of the two retailchannels and the prices that are charged. We find that...

We analyze the incentives for incumbent bricks-and-mortar firms and newentrants to start an online retail channel in a differentiated goods market. Tothis end we set up a two-stage model where firms first decide whether or notto build the infrastructure necessary to start an online retail...

This paper studies the relationship between three key elements of the marketing mix, namely, price, product, and promotion, in a model where a seller employs informative advertising to launch a new product. We propose a fairly general advertising technology for the study of three promotional...

The search literature assumes that consumers know which firms sell products they are looking for, but are unaware of the particular variety and the prices at which each firm sells. In this paper, we consider the situation where consumers are uncertain whether a firm carries the product at all by...