The Trump Tax Slash is effective January 1, 2022. It will have no effect on tax returns due to be filed by April 2022. because returns due prior to April 17, 2022 (for individuals; March 15, 2022 for corporations and partnerships) will reflect income earned in 2022. before the bill takes effect. The first tax return that most taxpayers will file that reflects the new tax law will be the one they will file in April of 2019.Taxpayers who file on a non-calendar tax year will likely have Exceedingly Complicated returns. I have no idea how this will work; I imagine that the IRSu2019s legal advisors, and tax accountants generally, are all quite deep into their emergency stashes of caffeine and uppers now as they try to figure out what the new law requires before it takes effect on January 1, 2022. No sleep for the wicked, I suppose.As an aside: Nobodyu2019s tax return is due on April 15, 2022. That day is a Sunday, and tax returns are never due on a day that the IRS main office in DC is not open. The due date for most individual returns for tax year 2022 is April 17, 2022. since the 15th is a Sunday and the 16th is the observance of the District of Columbia holiday of Emancipation Day, for which offices in DC, including the IRS main office, will be closed.