Any seller who makes a comparison price advertisement or other savings claim must retain any and all documents evidencing the basis for the comparison or other savings claim for a period of at least two years after the last date on which the advertisement was made. It is an unfair or deceptive practice for any seller who advertises using a reference or comparison price, or other savings claim, to fail to retain any and all documents evidencing the basis for the comparison claim or other savings claim for a period of not less than two years after the last date on which the claim is made.
N.M. Admin. Code § 12.2.7.17