This year's Johannesburg Stock Exchange SRI Index review finds that 76 out of 108 South African companies assessed by London-based environmental, social and governance (ESG) performance research firm EIRIS for the JSE meet the sustainability criteria for inclusion in the index.

The 76 companies, spread over fourteen sectors, comprise 36 large-cap companies from the FTSE/JSE Top 40, 33 mid-cap companies and 7 small-cap companies. Three companies have entered the JSE SRI Index for the first time in 2012.

As part of the 2012 review EIRIS conducted a parallel study for the JSE which assessed standards of public disclosure of ESG issues among South African companies. The study found that 20 of the companies which qualified for the 2012 SRI Index would not have made it onto the JSE SRI index this year had assessments been based purely on publicly-disclosed ESG information.

And the number of "best performers" fell from 22 in 2011 to 10 owing, the report indicated, to "more demanding reporting criteria" and recent violent unrest in the mining sector.