Adjustable Rate Mortgage (ARM)

Adjustable Rate Mortgage (ARM)

An Adjustable Rate Mortgage is one in which the interest rate fluctuates throughout the loan, typically in reaction to changes in the prime rate or LIBOR (London InterBank Offered Rate). The mortgage’s interest rate will be raised to reflect market rates due to the interest rate adjustment. A predetermined schedule for adjustments is followed when making adjustments.

ARMs often have lower initial interest rates than fixed-rate mortgages to make up for the possibility that the rate would rise over time. “Caps” that impose a limit on the first adjustment, periodic adjustments, and the total number of changes permitted over the loan’s term are there to safeguard you.

Importance of Using the Right Loan Program

An index, which is a set percentage, is used to account for the profit a lender makes on a loan.

Margin amounts are fixed throughout the loan’s duration and added to the index to determine the rate’s potential movement at each adjustment period.

Interest Rate = Index + Margin

Adjustment frequency, the reset date, reflects how frequently the interest rate changes. Most ARMs adjust once a year, although some do so monthly or even once every five years.

The Initial Interest Rate signifies the interest rate applicable until the first reset date. This rate establishes the initial monthly payment, which the lender might consider for your loan eligibility. The initial period with a fixed interest rate can range from as frequent as once a month to as extensive as a decade. In the past, the most prevalent type of adjustable-rate mortgage (ARM) was the one-year ARM, which underwent its first adjustment after a year and served as the benchmark. However, the current standard is the 5/1 ARM, where the initial fixed-rate duration spans five years, after which the rate is adjusted annually. This particular mortgage variant, blending a substantial fixed period with an even more extended adjustable period, is called a hybrid ARM.

The initial interest rate is often lower than the combined total of the current index and margin. This implies that your interest rate and monthly payment will likely increase when the first reset date occurs. Other well-known hybrid ARMs include the 3/1, 7/1, and 10/1 variations.

These hybrid ARMs, also known as 3/1, 5/1, 7/1, or 10/1 loans, maintain fixed rates for the initial 3, 5, 7, or 10 years, followed by rates that undergo annual adjustments after that.

Once the fixed-rate introductory phase ends, the ARM’s rate fluctuates in alignment with an index specified in the closing documents. The lender determines the index value, adds a margin, and then recalculates the borrower’s new rate and payment. This procedure repeats with each adjustment date

Borrowers receive a level of protection against significant fluctuations as Adjustable Rate Mortgages (ARMs) incorporate caps. These caps place limits on the extent to which ARM rates and payments can undergo adjustments.

Caps exist in various formats, with the most common being:

  1. Periodic rate cap: Restricts the rate’s permissible change within a given timeframe, often on an annual basis. This usually prevents the rate from increasing by more than a specific percentage over a single year.
  2. Lifetime cap: Imposes an upper limit on how much the interest rate can escalate throughout the loan’s lifespan.
  3. Payment cap: Found in certain ARMs, this cap confines the increase in monthly payment amount over the loan’s duration in dollars, rather than the rate’s change in percentage points.

Around the turn of the 21st century, lenders began promoting interest-only mortgages to middle-class borrowers, a concept previously reserved for wealthier clients. Typically adjustable, these mortgages require borrowers to make only interest payments for a designated period, often around 10 years. Following this phase, the rate adjusts based on a specified index, and the loan starts amortizing more rapidly. During the interest-only period, borrowers can opt to pay off some principal as well. Interest-only mortgages suit individuals with varying monthly incomes, such as commission-based professionals like salespeople, due to the flexibility they offer in adjusting monthly payments.

Certain ARMs feature a conversion option, enabling borrowers to convert their loans into fixed-rate mortgages for a fee. Others permit borrowers to make interest-only payments during a portion of their loan term to maintain lower payments. However, in general, ARMs tend to be more complex than fixed-rate loans.

To maintain flexibility in financial choices, it’s advisable to inquire with the mortgage lender about the ARM’s potential conversion to a fixed-rate mortgage. Additionally, ask if the ARM is assumable, meaning that when you sell your home, the buyer might qualify to take over your existing mortgage. This could be advantageous if mortgage interest rates are high at that time.

Major Indexes

The majority of ARM interest rates are linked to the performance of one of the following three key benchmarks:

  1. The weekly constant maturity yield on the one-year Treasury Bill. This reflects the yield from U.S. Treasury-issued debt securities, monitored by the Federal Reserve Board.
  2. 11th District Cost of Funds Index (COFI). This signifies the interest rate paid by financial institutions in the Western U.S. on their held deposits.

London Interbank Offered Rate (LIBOR). This denotes the interest rate at which central international banks lend to one another for substantial loans.


Easy!  Simply click "Contact Us" at the top of the page or click here:

We Are Very Trusted

Why People Choose Us


Your Satisfaction is our highest priority at all times


Our track record speaks for itself, proving our reliability.


Decades of expertise delivering backed by satisfied clients.


We maintain a culture and ensuring trust and accountability.

Our Quotes

Team Pope Home Loans Good Faith Estimate

Simply provide the necessary information and we’ll be in touch right away, you tell us when.  In the meantime, our calculator can provide the estimate you need to plan accordingly.

Model Your Loan Here

Total Principal Paid


Total Interest Paid


Monthly Payment


Months To Payoff


Borrowing :


Total You Will Pay: