JOHANNESBURG (Reuters) - South Africa's Capitec Bank expects first-half earnings to rise by as much as 22 percent, its said on Thursday, sending shares sharply higher and allaying investor fears about its exposure to unsecured lending after the collapse of a rival. Capitec, like rival African Bank or Abil, is an unsecured lender that traditionally targeted lower-income South Africans. It has, however, been shifting focus away from low-income earners and has been setting up branches in neighbourhoods where disposable incomes are higher. Following Abil's rescue by the central bank last month, ratings agency Moody's downgraded Capitec citing "heightened concerns regarding the inherent risks of Capitec's consumer-lending focus". But Capitec said there had been a marked increase in fees from transactions in the six months to end-August, when it also attracted more retail deposits. "Transaction income grew significantly not only because of an increase in client numbers, but also because we attracted clients in higher income groups who do more transacting," it said in a regulatory filing on Thursday. Its shares gained more than 8 percent at 230 rand, its biggest one-day jump since 2008, and outpaced a 0.4 percent rise by the All-Share index. "The details that they give are very positive, specifically that they've attracted clients in higher-income groups as well," said Jean Pierre Verster, an analyst at 36One Asset Management. The stock dropped more than 5 percent when Moody's announced its downgrade. The central bank has said its banking sector remains sound despite Abil's collapse, with impaired advances making up less than 4 percent of the industry's total loans. South African households have debt levels equal to about 75 percent of disposable income, making loan repayment a major burden for low-income households, where food costs alone account for one-third of expenditure.