Article Highlights: Tax Reform Prepayments W-4 Safe Harbor Payments Penalty Waivers & Exceptions Mitigating the Penalty Taxpayers are required to pre-pay their taxes for any tax year through payroll withholding, estimated tax payments or a combination of the two. Employees and retirees generally accomplish this through withholding, and self-employed individuals and those with investment income by paying quarterly estimated payments. The late-2017 passage of tax reform that became effective for 2018 and its radical changes added considerable confusion for taxpayers trying to determine how much they should prepay for 2018. This confusion was made worse because the existing W-4 that employees complete and that their employers use to determine the correct withholding was designed for prior law and does not work well with the new tax law. As a result, there has been ongoing concern by the IRS that many taxpayers will end up owing tax this year when they file their 2018 returns, even though they got a tax reduction due to the tax reform changes, simply because their pre-payments through withholding and estimated tax payments were not enough. For most of 2018, the IRS was issuing alerts that taxpayers may be under-withheld because of tax reform and the fact the W-4 could no longer be relied upon to produce a correct withholding amount. Taxpayers whose pre-payments are less than certain safe harbor amounts are penalized. Those safe harbors are: 90% of the current year’s tax liability or 100% of the prior year’s tax liability (110% where the prior year AGI is over $150,000 ($75,000 if married and filing separate returns).