26 CFR § 40.6071(a)-1 - Time for filing returns.
(a) Quarterly returns. Each quarterly return required under § 40.6011(a)–1(a)(2) must be filed by the last day of the first calendar month following the quarter for which it is made.
(b) Monthly and semimonthly returns—(1) Monthly returns. Each monthly return required under § 40.6011(a)–1(b) must be filed by the fifteenth day of the month following the month for which it is made.
(2) Semimonthly returns. Each semimonthly return required under § 40.6011(a)–1(b) must be filed by the last day of the semimonthly period (as defined in § 40.0–1(c)) following the semimonthly period for which it is made.
(c) Fees on health insurance policies and self-insured health plans—(1) Specified health insurance policies. A return that reports liability for the fee imposed by section 4375 must be filed by July 31 of the calendar year immediately following the last day of the policy year. For issuers that determine the average number of lives covered under the policy for section 4375 using the member months method under § 46.4375–1(c)(2)(v) or the state form method under § 46.4375–1(c)(2)(vi), the return must be filed by July 31 of the immediately following calendar year. Thus, for example, a return that reports liability for the fee imposed by section 4375 for the year ending on December 31, 2012, must be filed by July 31, 2013.
(2) Applicable self-insured health plans. A return that reports liability for the fee imposed by section 4376 for a plan year must be filed by July 31 of the calendar year immediately following the last day of the plan year. Thus, for example, a return that reports liability for the fee imposed by section 4376 for the plan year ending on January 31, 2013, must be filed by July 31, 2014.
(d) Effective/Applicability date. Paragraphs (a) and (b) of this section apply to returns for calendar quarters beginning on or after October 1, 2001, and paragraph (c) of this section applies to returns that report liability imposed by section 4375 or 4376.