Black South Africans own nearly 10% of the country's top listed firms, five times as much as had been previously thought, a survey has revealed.

Of the total share value of the top 115 firms listed on Johannesburg's stock exchange, stock worth 143.5bn rand (�9.3bn, $14.5bn) is owned by "historically disadvantaged communities", say analysts at think tank Empowerdex.

And even though the vast majority of shares is still held by South Africa's old establishment, the amount of stock held by blacks is much higher than the 30bn rand bandied about in previous estimates.

"This is good news," Empowerdex chief executive Vuyo Jack told BBC News Online.

"The influence greater ownership by historically disadvantaged communities could have on companies listed on the stock exchange could be tremendous."

Firms would be encouraged to champion empowerment issues, Mr Jack said.

The survey included shares owned by blacks both directly and indirectly through, for example, pension funds.

Conflicting report

However, the findings clashed with those of a separate report, which showed a decline of black ownership of listed firms.

The number of black-owned firms listed on the Johannesburg Stock Exchange has fallen to 23, compared with 38 three years ago, the National Economic Development and Labour Council said.

The council blamed the slide, which followed four year's of growth in the number of black-owned listed firms, on a lack of confidence among financial institutions.

Mines targeted

South Africa's government has this year stepped up efforts to boost the shares of economic riches accruing to blacks, who account for 40 million of the country's population of 45 million.

Plans which would see one quarter of South Africa's existing mines be owned by black-run firms within a decade were last month welcomed by mining firms, which had baulked at earlier proposals.

But while the sector has been the focus of empowerment efforts, the Empowerdex report revealed that the proportion of mining company shares owned by blacks was, at 7%, marginally below average.

The black shareholding in the real estate sector was 1%.

Company ratings

Empowerdex, formerly named Eedex, will in February publish company-by-company ratings which, while potentially "embarrassing" for some firms, would also highlight those which have taken steps to promote equality.

The ratings, judged on issues such as management, skills training and ownership, could be used by the government to support its equality drive by procuring from more empowerment-oriented firms.

Companies would also be able to assess the costs of various empowerment measures, helping them plan for orderly reform, said Mr Jack, a trained accountant.