26 U.S.C. § 859
Adoption of annual accounting period
(a) General rule
For purposes of this subtitle—
(1)
a real estate investment trust shall not change to any accounting period other than the calendar year, and
(2)
a corporation, trust, or association may not elect to be a real estate investment trust for any taxable year beginning after October 4, 1976 , unless its accounting period is the calendar year.
Paragraph (2) shall not apply to a corporation, trust, or association which was considered to be a real estate investment trust for any taxable year beginning on or before October 4, 1976 .
(b) Change of accounting period without approval
Notwithstanding section 442, an entity which has not engaged in any active trade or business may change its accounting period to a calendar year without the approval of the Secretary if such change is in connection with an election under section 856(c).
(Added Pub. L. 94–455, title XVI, § 1604(i)(1) , Oct. 4, 1976 , 90 Stat. 1752 , § 860; renumbered § 859 and amended Pub. L. 95–600, title III, § 362(d)(6) , title VII, § 701(t)(1), Nov. 6, 1978 , 92 Stat. 2852 , 2911; Pub. L. 99–514, title VI, § 661(c) , Oct. 22, 1986 , 100 Stat. 2300 .)