loss or destruction of the vehicle, (4) payoff of the loan with cash to save on the interest cost, and (5) refinancing of the loan at a lower interest cost. Prepayments due to repossessions and subsequent resale are sensi- tive to the economic cycle. In recessionary economic periods, prepay- ments due to this factor increase. While refinancings may be a major reason for prepayments of mortgage loans, they are of minor impor- tance for automobile loans. Moreover, the interest rates for the automo- bile loans underlying several issues are substantially below market rates if they are offered by manufacturers as part of a sales promotion. Prepayments for auto loan-backed securities are measured in terms of the absolute prepayment speed (ABS). The ABS is the monthly pre- payment expressed as a percentage of the original collateral amount. Recall that the SMM (monthly CPR) expresses prepayments based on     the prior months balance. There is a mathematical relationship between the SMM and the ABS measures.1   Payment Structure There are auto loan-backed deals that are passthrough structures and paythrough structures. A typical passthrough structure for an auto loan- backed deal is as follows:2     Tranche Amount ($) Average Life (Years) Coupon Rate   A $187,050,000 1.87 Fixed B 18,499,000 1.87 Fixed IO 6,000,000 1.46 Fixed     In this typical passthrough structure there is a senior tranche (A) and a subordinated tranche (B). There is also an interest-only class. While more deals are structured as passthroughs, this structure is typically used for smaller deals. Larger deals usually have a paythrough structure. As an illustration, consider auto-loan backed securities issued from the Chase Manhattan Auto Owner Trust 2001-A displayed in the Bloomberg screen in Exhibit 10.2. Note in this typical paythrough structure, the senior pieces are tranched to create a range of average lives. The subordinated piece typi- cally is not tranched.   Credit Card Receivable ABS Credit cards are originated by banks (e.g., Visa and MasterCard), retail- ers (e.g., JCPenney and Sears), and travel and entertainment companies