The first results of a large-scale tax reform of 2017 are analyzed. The effects and consequences of the tax reform are estimated based on a comparison of macroeconomic indicators of the American economy in the period 2013-2017, and in the subsequent period. The tax cut, starting in January 2018, had a relatively small effect on the acceleration of U.S. economic growth compared to the pre-reform period – by 0.6-0.7% on yearly basis. The main positive impact of tax reform has revealed itself in the investment activity of the business non-farm sector of the U.S. economy, particularly in the form of rapidly growing investments in intangible assets which represent the capital deepening which stipulate the scientific and technological progress. The record-breaking tax cuts on corporate sector profits of the U.S. economy were used by senior management of the leading US corporations to buy back shares from company owners, which markedly weakened the impact of tax reform on accelerating U.S. economic growth. Tax reform increased inequality in the distribution of income in American society in favor of its richest strata, which turned into a small increase in real wages and salaries of the bulk of the working people. The reform contributed to a noticeable increase in the repatriated earnings of the U.S. corporations to the U.S. economy, although in general the problem of shifting profits in offshore zones remains one of the most acute problems in the development of the U.S. economy. Tax reform has further intensified the crisis in the U.S. federal finance system and contributed to the fact that the chronic federal budget deficits under the Trump administration reached an annual size of $1 trillion.