Receivables manager Collection House yesterday reported net profit of $5.5 million for the six months to December, a 62 per cent increase on the previous corresponding period.Collection House chief executive Tony Aveling cautioned that the second half could be more subdued.  He said lenders might be offering less of their impaired debt for sale, given the improved economic conditions, and they may be asking a higher price for what they do sell.Credit Corp last week cited similar factors as restricting the opportunity to buy ledgers from long-standing customers.Almost 70 per cent of Collection House's revenue comes from recovering debts it has purchased from lenders. A quarter comes from collecting on commission and the balance comes from receivables management.Aveling said the group took a conservative approach during the financial crisis, limiting the growth in its book and reducing borrowing costs. Revenue for the half, at $52.8 million, was unchanged from the previous corresponding period. The improved performance was a result of lower collection costs and other expenses.The company has plenty of spare financial capacity. Operating cash flow was almost double ledger purchase costs.Aveling said:  "If there had been sufficient debt at the right price we would have bought more."When times were hard our focus was on recoverability. Now we have more capacity and we are in a position to expand."The issue in the current half is that there is not a lot of volume in the market and others may be chasing it. We have to be careful about what price we pay."The company has $22 million of funding available to purchase debt, made up of  $12 million of undrawn limits and $10 million in an increased bank facility.