The Impact of Social Screening on Portfolio Performance at the Nairobi Securities Exchange

Abstract

This study sought to determine whether applying social screens to a portfolio would affect the portfolio's performance. Two portfolios were formulated each comprised of 20 firms. One comprised of the NSE 20-share index firms and the second comprised 20 firms that passed the negative screening criterion that was employed. The causal research design approach was used. The target population was all the 58 firms listed at the NSE. The risk and risk-free returns were computed using the Sharpe indices approach. Monthly and annual returns were calculated for years 2007 - 2011. The standard deviation and beta were the chosen risk measures. T-tests were used to determine whether there was significant difference between the risk and returns of the two portfolios. In terms of monthly and annual raw returns, the socially screened portfolio was seen to outperform the conventional portfolio. The conventional portfolio had a higher average Sharpe ratio than the socially screened portfolio hence it outperformed the socially screened portfolio when compared in terms of returns and total risk. The findings of this study revealed mixed results in the portfolio performance. The socially screened portfolio outperformed the conventional portfolio in relation to total risk but in relation to systematic risk and performance, the conventional portfolio outperformed the socially screened portfolio. The results showed that social screening has no significant impact in influencing investors' decision on which firm to invest in or not. The study recommends formulation of an additional index to capture the periodic performance of socially screened top-20 companies; and utilization of alternate performance measures such as the Treynor and Jensen portfolio performance measures to reinforce the findings of the present study.