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💰Mortgage & Financing

Index (ARM)

Definition

The benchmark interest rate used to calculate adjustable-rate mortgage (ARM) adjustments. Common indices include SOFR (Secured Overnight Financing Rate), Prime Rate, or Treasury rates. Your ARM rate = Index + Margin.

Example

If SOFR is 4.8% and your ARM margin is 2.5%, your fully indexed rate is 7.3%. Rate caps may prevent you from reaching this rate immediately at reset.

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