“…Most prominently, Stock and Watson (2002) advocate summarizing large panels of predictor variables into a small number of principal components, which are then used for forecasting purposes in a dynamic factor model. Alternative approaches include combining forecasts based on multiple models, each including only a small number of variables (Faust and Wright, 2009;Wright, 2009;Aiolfi and Favero, 2005;Huang and Lee, 2010;Rapach et al, 2010), partial least squares (Groen and Kapetanios, 2008), and Bayesian regression (De Mol et al, 2008;Bańbura et al, 2010;Carriero et al, 2011). Stock and Watson (2009) find that for forecasting macroeconomic time series, the dynamic factor model approach is preferable to these alternatives; see also Ng (2007, 2009) and Ç akmaklı and van Dijk (2010) for successful applications in finance.…”