What are the two components that determine the fully indexed rate on an ARM?

• A. Principal and interest
• B. Index and margin
• C. APR and points
• D. Balloon payment and rate

Answer: (B)

In an adjustable-rate mortgage, the rate that actually affects each adjustment period—the fully indexed rate—comes from two parts: the current index and the margin. The index is a fluctuating market rate that can rise or fall over time (like SOFR or another benchmark). The margin is a fixed percentage set in the loan terms that the lender adds to whatever the index is at adjustment. When you add the two together, you get the fully indexed rate that will be used for that period, typically subject to caps or floors.

For example, if the index is 2.5% and the margin is 3.0%, the fully indexed rate would be 5.5% for that adjustment. This concept is distinct from payments (principal and interest), loan costs (APR and points), or loan features like balloon payments.