12 CFR Part 34, Subpart B (Adjustable-Rate Mortgages)

Updated May 17, 2026

12 CFR Part 34, Subpart B, is a federal regulation that defines and sets general rules for national banks offering Adjustable-Rate Mortgage (ARM)s (ARMs).

Key Provisions

• Definition of ARM: The regulation defines an ARM as an extension of credit secured by a lien on a one-to-four family dwelling where the lender, by agreement with the Borrower (Consumer), may periodically adjust the interest rate,.
• Index Requirements: Loan documents for ARMs must link interest rate changes to an index that is readily available to and verifiable by the borrower and beyond the control of the bank. This ensures transparency and prevents lenders from manipulating the rate.

This regulation ensures that ARMs offered by national banks adhere to specific standards, particularly regarding the transparency and objectivity of interest rate adjustments.