Tax Law Simplification and Improvement Act of 1983

[AI summary unavailable — showing source text] Tax Law Simplification and Improvement Act of 1983 - Title I: Revision and Simplification of Estimated Income Tax for Individuals - Amends the Internal Revenue Code to revise provisions dealing with the quarterly payment of estimated tax by individuals. Establishes the amount of the penalty for underpayment of estimated tax at the amount of the underpayment for the period of underpayment, plus interest on such amount. Revises the schedule for the payment of estimated tax installments. Specifies that the amount of the required annual estimated tax payment shall be the lesser of 80 percent of the current tax shown on the taxpayer's return or 100 percent of the preceding year's tax liability. Permits lower estimated tax payments if the taxpayer can show that the installment payments made over the year were adequate for each quarter based on an annualized income concept. Exempts a taxpayer from an estimated tax penalty: (1) where the tax liability is less than $500; (2) where there is no tax liability for the preceding taxable year; or (3) where there is reasonable cause for the underpayment. Exempts a taxpayer from a penalty for underpayment of estimated tax for the fourth quarter if …