Rwanda, which wants to become a hub for finance in Africa, has said it plans to sell the partly state-owned bank, known as BRD because of its French name Banque Rwandaise de Developpement, as part of a broader privatisation programme.
"We're acquiring the government's stake through this process which is just over 75%, Diamond told a news conference in Kigali on Sunday.
Growth
Rwandan Finance Minister Claver Gatete said that so far only a preliminary memorandum of understanding had been signed but he added that the deal could be finalised within two months.
"The government of Rwanda is committed to privatisation in a sense that attracts foreign direct investments, gives investors good business opportunities and also boosts economic growth," he said at the news conference.
The BRD deal would involve splitting the bank's activities between its commercial operations, to be run by Atlas Mara, and its development work, in which the government would have a role.
Atlas Mara was created by Diamond's Atlas Merchant Capital and Mara Group Holdings, set up by Ugandan-born entrepreneur Ashish Thakkar in 1996.
Financial
Atlas Mara said last month it would acquire Botswana-based ABC Holdings (BancABC) and ADC African Development Corporation AG.
It plans to build a sub-Saharan African financial services group, according to a statement announcing the deal.
"BRD is an opportunity for Atlas Mara to create a privately run financial services group in Rwanda, which will serve as a platform for them to expand into the attractive east African market," it said.
That will be a boost to plans to build a financial industry for the region based in Rwanda, where nine commercial banks now operate although none are major global players.
Rwanda has said it wants to attract more institutions.