Northam Platinum dropped the most in four months in Johannesburg trading after saying higher borrowing costs and a tax charge would erode first-half profit. Northam declined as much as 9.8 percent, the biggest intraday drop since September 21, before recovering to trade 1.14 percent higher at R39.80 by 5pm. Earnings would probably be 30 percent to 45 percent lower in the six months to December compared with a year earlier, it said in a statement. “The anticipated decline in earnings reflects the finance costs incurred on borrowings and a higher effective tax charge during the period under review,” Northam said. The company sold R1.25 billion of bonds due 2015 in September to expand its operations. – Bloomberg