# Treas. Reg. § 301.6166-1: Extension of time for payment of estate tax where estate consists largely of interest in closely held business.

Source: eCFR as of 2026-10-19 <https://www.ecfr.gov/current/title-26/section-301.6166-1>. Interprets 26 U.S.C. § 6166.

For provisions relating to the extension of time for payment of estate tax where estate consists largely of interest in closely held business, see §§ 20.6166-1 to 20.6166-4, inclusive, of this chapter (Estate Tax Regulations).