of credit for small employer pension plan startup costs to employers which join an existing plan (a) In general Section 45E(d)(3)(A) of the Internal Revenue Code of 1986 is amended by striking effective and inserting effective with respect to the eligible employer . (b) Effective date The amendment made by this section shall apply to eligible employer plans which become effective with respect to the eligible employer after the date of the enactment of this Act. 6. Harmonization of treatment of IRAs with Employer plans (a) Statute of limitations Section 6501(l) of the Internal Revenue Code of 1986 is amended— (1) in paragraph (1), by inserting (other than with respect to an individual retirement plan) after section 4975 , and (2) by adding at the end the following new paragraph: (4) Individual retirement plans For purposes of any tax imposed by section 4973, 4974, or 4975 in connection with an individual retirement plan, the return referred to in this section shall be the income tax return filed by the person on whom the tax under such section is imposed for the year in which the act (or failure to act) giving rise to the liability for such tax occurred. In the case of a person who is not required to file an income tax return for such year— (A) the return referred to in this section shall be the income tax return that such person would have been required to file but for the fact that such person was not required to file such return, and (B) the 3-year period referred to in subsection (a) with respect to the return shall be deemed to begin on the date by which the return would have been required to be filed (excluding any extension thereof). . (b) Effective date The amendments made by this section shall apply to plan years beginning after December 31, 2020.