Abstract: A computer collection model of charged off credit card debt is used to determine the amount and types of commission that should be paid to collection entities and to determine whether and when certain deals should be offered on the debt. The commissions can be plural consecutive percentage commission rates, progressively larger retroactive commission rates, a periodic percentage commission rate resulting in equal profits per period, a fixed collector profit, or another commission arrangement. The model can be designed to maximize at least liquidation rates and/or profitability.