26 CFR § 1.909-4 - Coordination rules.

---
identifier: "/us/cfr/t26/s1.909-4"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "26 CFR § 1.909-4 - Coordination rules."
title_number: 26
title_name: "Internal Revenue"
section_number: "1.909-4"
section_name: "Coordination rules."
chapter_name: "INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY"
subchapter_number: "A"
subchapter_name: "INCOME TAX"
part_number: "1"
part_name: "INCOME TAXES"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "26 U.S.C. 7805, unless otherwise noted."
regulatory_source: "T.D. 6500, 25 FR 11402, Nov. 26, 1960; 25 FR 14021, Dec. 21, 1960; T.D. 9989, 89 FR 17606, Mar. 11, 2024, unless otherwise noted."
cfr_part: "1"
---


# 1.909-4 Coordination rules.

(a) *Interim rules.* The principles of paragraph (g) of § 1.909-6 apply to taxable years beginning on or after January 1, 2011.

(b) *Effective/applicability date.* This section applies to taxable years ending after February 9, 2015. See 26 CFR 1.909-4T (revised as of April 1, 2014) for rules applicable to taxable years beginning on or after January 1, 2011, and ending on or before February 9, 2015.

[T.D. 9710, 80 FR 7332, Feb. 10, 2015]