The estate tax return required under section 7444 of this title shall be filed within nine months of the death of the decedent. Prior to expiration of the filing period, executors may apply for a six-month extension. (Added 1969, No. 269 (Adj. Sess.), § 1, eff. date, see note under § 7401 of this title; amended 2009, No. 1 (Sp. Sess.), § H.34.)