SOUTH African companies have emerged as leading contenders for controlling stakes in two Nigerian firms in a move analysts said underlined the growing economic ties between Africa’s two dominant countries. The Nigerian privatisation agency said that South Africa’s Addax Holdings SA had offered 1,3 billion naira 30%, of oil marketing company Unipetrol The Bureau of Public Enterprises said that another South African firm, Loita Capital Partners, separately offered 927,3 million naira for or a 26% stake of NAL Merchant Bank. South African investors turned their sights on Nigeria after the West African country returned to democratic rule in May 1999. Last month, another South African company, Engen, tendered for a controlling 60 percent stake in oil marketing firm National Oil.