JOHANNESBURG (Reuters) – South African investment firm RMB Holdings Ltd. plans to expand its portfolio by buying a stake in unlisted Atterbury, builder of the Mall of Africa, one of the largest shopping venues in the country.

RMB Holdings Limited, which holds a 34 percent stake in FirstRand, the largest banking group by value in Africa’s most industrialised economy as its only major asset, said on Tuesday it will buy 25.01 percent of Atterbury.

Although it did not put a price on the cost of investment for Attebury, RMB Holdings said in the statement it would fund the deal through preference shares.

RMB Holdings said in a statement it aimed to use Atterbury to spearhead its retail and industrial property business.

The Mall of Africa, which opened its doors last week, targets consumers in Midrand a middle-class suburb north of the commercial hub of Johannesburg.

“We thought it was a missing element of our overall portfolio,” RMB Holdings Chief Executive Herman Bosman told Reuters, referring to property investments.

Shares in RMB Holdings fell 4.60 percent on the bourse by 1358 GMT, as stocks tumbled across the board tracking a sell-off in emerging markets.

(Reporting by Tanisha Heiberg; Editing by James Macharia)