15 U.S. Code § 1606 - Determination of annual percentage rate
Where a creditor imposes the same finance charge for balances within a specified range, the annual percentage rate shall be computed on the median balance within the range, except that if the Bureau determines that a rate so computed would not be meaningful, or would be materially misleading, the annual percentage rate shall be computed on such other basis as the Bureau may be regulation require.
The disclosure of an annual percentage rate is accurate for the purpose of this subchapter if the rate disclosed is within a tolerance not greater than one-eighth of 1 per centum more or less than the actual rate or rounded to the nearest one-fourth of 1 per centum. The Bureau may allow a greater tolerance to simplify compliance where irregular payments are involved.
The Bureau may authorize the use of rate tables or charts which may provide for the disclosure of annual percentage rates which vary from the rate determined in accordance with subsection (a)(1)(A) of this section by not more than such tolerances as the Bureau may allow. The Bureau may not allow a tolerance greater than 8 per centum of that rate except to simplify compliance where irregular payments are involved.
In the case of creditors determining the annual percentage rate in a manner other than as described in subsection (d) of this section, the Bureau may authorize other reasonable tolerances.
 So in original.
2010—Pub. L. 111–203 substituted “Bureau” for “Board” wherever appearing.
1980—Subsec. (c). Pub. L. 96–221, § 607(a), substituted provisions relating to allowable tolerances for purposes of compliance with disclosure requirements, for provisions relating to rounding off of annual percentage rates which are converted from single add-on or other rates.
Subsec. (e). Pub. L. 96–221, § 607(b), struck out reference to subsection (c) of this section.
Subsec. (f). Pub. L. 96–221, § 607(c), struck out subsec. (f) setting forth requirements for form of expressing percentage rates prior to Jan. 1, 1971.
Amendment by Pub. L. 96–221 effective on expiration of two years and six months after Mar. 31, 1980, with all regulations, forms, and clauses required to be prescribed to be promulgated at least one year prior to such effective date, and allowing any creditor to comply with any amendments, in accordance with the regulations, forms, and clauses prescribed by the Board prior to such effective date, see section 625 of Pub. L. 96–221, set out as a note under section 1602 of this title.