Davids, Goliaths, and Business Cycles
研究发现一个简单直观的变量：大盘股与小盘股权重变化（GVD），能反映贴现率随经济状况的变动，是预测市场回报的最佳单一指标，对投资者和宏观经济学家有参考价值。
We show that a simple, intuitive variable, Goliath versus David (GVD), reflects time variation in discount rates related to changes in aggregate business conditions. GVD is the annual change in the weight of the largest 250 firms in the aggregate stock market and is motivated by research that shows that small firms are more severely impacted than large firms by economic shocks due to differences in access to external finance. We find that GVD is the best single predictor of out-of-sample market returns among traditional predictors, predicting quarterly market returns with an out-of-sample R 2 of 6.3% in the 1976–2011 evaluation period.