Many years ago, the authors demonstrated that there is much greater dimensionality to the stock market than is suggested by the one-factor capital asset pricing model. Investors today continue to underestimate the market's dimensionality through their recent embrace of “smart beta”...

Investors who have the flexibility to invest both long and short can benefit from both “winners” and “losers.” This will be especially advantageous if the latter — the short-sale candidates — are less efficiently priced than the winners — the purchase candidates. This is likely to...