Johannesburg – RMB Holdings Ltd, which owns a stake in South Africa’s largest bank by market value, agreed to buy 25 percent of Atterbury Property Holdings as part of a plan to expand into real estate and diversify earnings.

RMB Holdings, known as RMH, will provide capital and “long-term focus to expand Atterbury and assist in executing on its development pipeline and broader growth ambitions,” the Johannesburg-based investment company said in a statement on Tuesday, without disclosing the value of the transaction.

The acquisition of Atterbury marks the first major deal by RMH since the company spun off its insurance businesses into Rand Merchant Investments Holdings in 2011. Atterbury developed the Mall of Africa, which opened last week as the largest first-phase retail development in southern Africa, covering 130 000 square metres of stores.

RMH – which was built out of a company founded by some of South Africa’s richest men, GT Ferreira, Laurie Dippenaar and Paul Harris – is the biggest shareholder in FirstRand, with a 34 percent stake. Businesses under their control have also helped start or grow companies such as Discovery, owner of South Africa’s largest medical-insurance administrator, OUTsurance Insurance Company, a property and casualty insurer, and MMI Holdings, a life insurer and money manager.

RMH declined 2.4 percent to 56.71 rand by 9.52am in Johannesburg, the lowest since April 11, and biggest decline among the seven-member FTSE/JSE Africa Banks Index.