“…We consider three dimension-reduction techniques: The first takes the cross-sectional average of the individual predictors, the second extracts the first principal component from the set of predictors Ng (2007, 2009)), and the third, an implementation of partial least squares (PLS; Wold (1966)), extracts the first target-relevant factor from the set of predictors Pruitt (2013, 2015), Huang et al (2015)). As indicated previously, the forecasts based on strategies 3 Our study complements recent studies that employ machine-learning techniques to predict stock returns using alternative predictor variables in high-dimensional settings, including Rapach, Strauss, and Zhou (2013); Chinco, Clark-Joseph, and Ye (2019); Rapach et al (2019);Freyberger, Neuhierl, and Weber (2020); Gu, Kelly, and Xiu (2020); Kozak, Nagel, and Santosh (2020); Avramov, Cheng, and Metzker (2021); Chen, Pelger, and Zhu (2021); Cong et al (2021); Han et al (2021);and Liu, Zhou, and Zhu (2021).…”