Oakbay Investments, owned by the Gupta family, signed a contract to export power-plant coal at a premium to what it gets from South Africa’s electricity utility, Chief Executive Officer Nazeem Howa said. “We signed our first export contract this week,” Howa said on a conference call Thursday. “The value of the export contract came in at close to 150 rand ($11) a ton more than the highest price we’re getting from Eskom,” he said, referring to the country’s state-owned power producer that uses coal for the bulk of its generation. The deal comes as the National Treasury investigates Eskom’s coal contracts and suppliers including Tegeta Exploration & Resources (Pty) Ltd., part-owned by the Guptas, who are friends with President Jacob Zuma and are in business with his son. Some ruling-party officials accused the family of trying to influence South African cabinet appointments Swiss commodities trader Vitol Group is interested in buying a stake in the Richards Bay Coal Terminal from Tegeta, a person with knowledge of the matter said last week. Purchasing the interest in Africa’s biggest coal-export facility from Optimum Coal Holdings Ltd. could give Geneva-based Vitol rights to ship about 8 million tons of the fuel annually. Glencore Plc, Anglo American Plc and South32 Ltd. are among shareholders in RBCT. Export Allocation Howa declined to comment on whether the export allocation was being sold. Oakbay Investments has “a relationship where one other party is using some of the allocation at the moment,” he said, only identifying it as a South African company. South Africa, the continent’s biggest coal producer, has high-quality reserves of the fuel, though shipments are constrained by limited port capacity. Only shareholders have an automatic right to export through Richards Bay, which accounts for almost all of the nation’s coal-shipping capacity. Oakbay hasn’t directly used any of the allocation, Howa said. Its first export contract “is an opportunity for us to grow quite significantly,” he said. Government contracts accounted for 8.9 percent of 2.62 billion rand of Oakbay Investment’s revenue in the 12 months through February, the company said in an e-mailed statement.