Retention of records
(e) Retention of records. (1) For plan years ending prior to September 3, 1974, a plan may be required to furnish proof that it met the requirements of section 414(f) and this section for each plan year ending prior to that date to the extent necessary to show the applicability of the 75 percent test provided in paragraph (c) of this section. (2) For plan years ending after September 2, 1974, a plan may be required to furnish proof that it met the requirements of section 414(f) and this section for 6 immediately preceding plan years.