– 5/1 Adjustable Rate Mortgage 5/1 ARM – the rate is fixed for a period of 5 years after which in the 6th year the loan becomes an adjustable rate mortgage (ARM). The adjustable rate is either tied to the 1-year treasury index or to the one-year London Interbank Offered Rate ("LIBOR"), and is added to a pre-determined margin (usually between.
What is a 5/1 ARM Mortgage? – Financial Web – How a 5/1 ARM Mortgage Works. The term 5/1 ARM means that you will get five years of a fixed interest rate, followed by one-year increments of adjustable rates. This means that for the first five years of the mortgage, you are going to have the same interest rate and the same monthly mortgage payment.