Thorn Group suffered a heavy fall in profit in the year to March, after a series of write-offs, provisions and costs associated with the closure of a business unit ate into underlying earnings. And there could be more bad news to come, with the company disclosing that it is the subject of an investigation into possible breaches of responsible lending rules that may result in fines.Thorn reported net profit of A$20.1 million for the 12 months to March - down 34.4 per cent from the previous corresponding period. Revenue was up 3.5 per cent to $304 million.Return on equity fell from 16.9 per cent in 2014/15 to 10.4 per cent in the year to March.The company said its underlying net profit was $30.3 million, compared with $30.6 million in the previous corresponding period.Thorn Group chief executive James Marshall said he was pleased with the underlying performance of the business.However, there was a substantial increase in Thorn's borrowing, which grew 37.4 per cent, and an increase in gearing from 38.7 per cent to 53.2 per cent.Profit was reduced by $11.8 million pre-tax after the company wrote off goodwill attributable to its 2011 acquisition of the debt collection agency NCML, closed its consumer lending business and created a provision for customer refunds in its consumer leasing business. The company said these were all one-offs.The business finance division was Thorn's best performing unit, increasing earnings before interest and tax by 106 per cent to $14 million. Much of this improvement was due to the first full-year contribution of the receivables finance business Cash Resources Australia (now Thorn Trade & Debtor Finance), which Thorn acquired at the end of 2014.The other business units did not fare so well. EBIT for receivables management fell from $2.3 million to $1.3 million. The company said this result was affected by a change to its methodology for valuing its purchased debt ledgers to bring Thorn into line with the practice of its peers in the receivables management industry.The company's biggest business unit, consumer leasing, suffered a 35.7 per cent fall in EBIT to $49.7 million.Thorn Group chief executive James Marshall said there was a slowdown in the March half as tighter income and expenditure verification requirements had a negative impact on the inquiry conversion rate. The customer refund provision also had an impact.Consumer leasing originations were up 6.4 per cent and receivables were up 35.7 per cent.Marshall said Thorn was working with the Australian Securities and Investments Commission on an investigation into its responsible lending practices. The investigation was ongoing and there were "a number of potential outcomes", including fines, he said."We have seen an increased regulatory presence in our industry over the past 12 months. It will require an evolution of systems on our part. We will make any necessary adjustments," Marshall said.