Verheyden, De Moor, and Campenhout (2014) 

Verheyen, Tim, Lieven De Moor, and Geert Van Campenhout.  “Revisiting the SRI performance debate: A new way of defining and classifying mutual funds.”  Working paper (KU Leuven/HU Brussels), May 27, 2014.

From the authors' abstract:  "Overcoming the naive dichotomous distinction between SRI-marketed and conventional funds, we confirm most earlier research and find that differences in the fund’s approach towards investing with respect to a broad definition of SRI do not impact its risk-adjusted financial performance. From our analysis using a more sophisticated definition and classification of mutual funds we can conclude that there are no financial motives in favor, nor against investing in a socially responsible way. Hence, the SRI decision should be based on extra-financial grounds."