The SECURE Act now allows employers to adopt retirement plans after the close of the employer's tax year (by the due date, including extensions, for filing its tax return). The employer may elect to treat the plan as having been adopted as of the last day of the tax year (the new rule applies after December 31, 2019).If an employer adopts a plan prior to the tax filing deadline in 2021 and treats the plan as having been adopted as of the last day of the employer's 2020 tax year, the plan sponsor is not required to file Form 5500 for the plan year that begins during the employer's 2020 tax year. The first Form 5500 required to be filed instead will be the 2021 Form 5500. The plan sponsor should check a box on the 2021 Form 5500 indicating that the employer elects to treat the plan as retroactively adopted as of the last day of the 2020 tax year. For defined benefit plans, the employer must attach a 2020 Schedule SB to the 2021 Form 5500 or Form 5500-SF, in addition to a 2021 Schedule SB. For more information on the Form 5500 filing requirements, see Q 3777.