I imagine that legally the new owner of the debt is entitled to charge interest, but they would have no right to charge more than the original debtor had. What they do is another matter, and nothing stops them cutting a deal, along the lines of starting with $A, but if you agree to pay $B a fortnight for C fortnights, we will fully acquit the debt.
The better quality debt portfolios probably cost about 20% of face value, so if the buyers gets 60% of face value paid, they make a gross of profit of 40%. CCP tends to amortise PDLs at about 47%, of collections, which suggest to me that the gross profit is about 53%. About 80% of all CCP's collections come from negotiated repayment plans, so I imagine CCP offers some sweetener to induce debtors to enter such arrangements.
I suspect that at that gross profit level, firms like CCP, CLH and PNC would not differ much. The difference in NPATs is significant, mainly because CCP borrows much less, and being the largest of the three, it gains some economies of scale.
