Receivables management company Collection House increased earnings by 24 per cent in the December 2011 half-year, citing strong growth in its purchased debt ledger as the main reason for the improved result.Collection House yesterday reported a net profit of A$6.4 million for the six months to December - up from $5.1 million in the previous corresponding period.Revenue from debt collections and commissions rose 12 per cent, from $55.9 million in the six months to December 2010 to $62.7 million in the latest half.The company spent $31 million on debt ledgers in the half, an increase of 27 per cent on the previous corresponding period. In November, the company extended its credit facility from $85 million to $100 million and raised $5.8 million of new equity capital to fund its expansion. Collection House chief executive Matthew Thomas said inventory levels would continue to grow in the second half.