a single employer. (B) Exception (i) In general Subparagraph (A) shall not apply to any person who establishes to the satisfaction of the Secretary that such person has a substantial and legitimate business reason for failing to provide a written policy described in paragraph (1) or (2). (ii) Substantial and legitimate business reason For purposes of clause (i), the term substantial and legitimate business reason shall not include the operation of a separate line of business, the rate of wages or category of jobs for employees (or any similar basis), or the application of State or local laws relating to family and medical leave, but may include the grouping of employees of a common law employer. , and (3) in subsection (d)(2), by inserting , as determined on an annualized basis (pro-rata for part-time employees), after compensation . (b) Effective date The amendments made by this section shall take effect as if included in section 13403 of Public Law 115–97 . 5. GAO study of impact of tax credit to promote access to paid family and medical leave (a) Study Not later than June 30, 2022, the Comptroller General of the United States, in consultation with the Secretary of the Treasury and the Secretary of Labor, shall— (1) complete a study that— (A) examines the effectiveness of the tax credit for paid family and medical leave authorized under section 45S of the Internal Revenue Code of 1986 in terms of— (i) increasing access to paid family and medical leave among qualifying employees