Debt buyer Credit Corp's long-term investment in building a business in the United States paid off for the group in 2018/19, with the US debt ledger purchasing business making the biggest contribution to the company's earnings growth.Credit Corp reported net profit of A$70.3 million for the year to June - an increase of 9 per cent over the previous corresponding period. Revenue was up 8 per cent to $324.2 million.The segment report shows that revenue for the Australian and New Zealand debt ledger purchasing business fell 3.1 per cent to $189.5 million and segment profit (EBITDA) was up just 1.5 per cent to $78.9 million.Revenue for the US debt ledger purchasing business rose 70.2 per cent to $40.8 million and segment profit rose almost three-fold to $7.8 million.Revenue for the Australian and New Zealand consumer lending business rose 18.4 per cent to $93.9 million and segment profit rose 25.2 per cent to $28.8 million.Credit Corp chief executive Thomas Beregi said the US business, which was launched in 2010, was on track to be as big as the local business. He said debt buying conditions in the US market were favourable.He said the consumer lending business, Wallet Wizard, was able to pick up business as prime lenders tightened their lending standards. New customer number increased by 18 per cent and settlement rose 17 per cent to more than $200 million.The results for the Australian and New Zealand debt ledger purchasing business reflected the fact that there had been reduced debt purchasing over the past couple of years.Beregi said investment picked up late in the financial year. He said the company expected to continue investment at the current rate.He said that one impact of the Hayne royal commission was that lenders have become more sensitive about the level of compliance of the debt buyers and collection agents they deal with. "Credit Corp's compliance superiority is increasingly valued by our clients and is enabling us to hold, and in some cases grow, market share despite aggressive bidding," he said.The company has total banking facilities of $350 million - up from $280 million in 2017/18. It has "substantial capital headroom" to fund its investments.Credit Corp has 786,000 accounts on its book - up from 710,000 in June 2018. The face value of the portfolio is $6.4 billion.The face value of the 157,000 accounts under arrangement was steady at $1.3 billion and debt collections were up 6 per cent over the previous year.