Adjustable Rate Mortgages: Valuation

A simulation method is employed to value Adjustable Rate Mortgages, (ARMS). It is used to price two typical instruments: an ARM linked to a Treasury interest rate and an ARM linked to a “Cost of Funds” Index. Contractual provisions such as the margin over the index, caps and floors on the ARM’s rate or on the monthly prepayment, reset frequency, and the “teaser” rate are examined for their influence on value. The effects of interest rate trend and volatility are also analyzed.