Figures & data
Since July 2017, we have constructed quintile portfolios based on the 12-month average ESG rating dispersion and track their average monthly value-weighted CAPM-alpha for the subsequent three months. We rebalance portfolios at the end of each rating-release month, thereby generating a time series of excess returns from August 2017 to April 2022. Panel A plots the time series of the spread in monthly CAPM-alpha between the two extreme quintile portfolios (bottom versus top). Panel B plots the cumulative spread in CAPM-alpha between the two extreme quintile portfolios.
Since July 2017, we have formed quintile portfolios and calculated buy-and-hold returns over holding periods ranging from 1 to 12 months without mid-way selling. We averaged these returns across all bottom (top) portfolios for each holding period and presented them as dots with connecting lines. Panel A shows results for overlapping holding periods, and Panel B displays the results for non-overlapping holding periods. We adopt a simple technique to avoid overlapping return observations. For a given holding period is h, we only consider observations gathered at time t = 0, h, 2h, 3h, … In this way, the return from time 0 to h does not overlap with the return from time h to 2h.