In yesterday’s Wall Street Journal Martin Feldstein elegantly dismantles Thomas Piketty’s Das Kapital for the 21st century. Piketty is a French economist whose book “Capital in the Twenty-First Century” has made the NY Times best seller list. In it, Piketty highlights growing income inequality in America and offers as a solution, confiscatory taxes. Piketty has long advocated for an 80% marginal tax rate and a tax on wealth. Feldstein calls out Piketty for “a flawed interpretation of U.S. income-tax data, and a misunderstanding of the current nature of household wealth.”
Mr. Piketty’s theoretical analysis starts with the correct fact that the rate of return on capital—the extra income that results from investing an additional dollar in plant and equipment—exceeds the rate of growth of the economy. He then jumps to the false conclusion that this difference between the rate of return and the rate of growth leads through time to an ever-increasing inequality of wealth and of income unless the process is interrupted by depression, war or confiscatory taxation. He advocates a top tax rate above 80% on very high salaries, combined with a global tax that increases with the amount of wealth to 2% or more.
The second problem with Mr. Piketty’s conclusions about increasing inequality is his use of income-tax returns without recognizing the importance of the changes that have occurred in tax rules. Internal Revenue Service data, he notes, show that the income reported on tax returns by the top 10% of taxpayers was relatively constant as a share of national income from the end of World War II to 1980, but the ratio has risen significantly since then. Yet the income reported on tax returns is not the same as individuals’ real total income. The changes in tax rules since 1980 create a false impression of rising inequality.
In 1981 the top tax rate on interest, dividends and other investment income was reduced to 50% from 70%, nearly doubling the after-tax share that owners of taxable capital income could keep. That rate reduction thus provided a strong incentive to shift assets from low-yielding, tax-exempt investments like municipal bonds to higher yielding taxable investments. The tax data therefore signaled an increase in measured income inequality even though there was no change in real inequality.
Mr. Piketty’s practice of comparing the incomes of top earners with total national income has another flaw. National income excludes the value of government transfer payments including Social Security, health benefits and food stamps that are a large and growing part of the personal incomes of low- and middle-income households. Comparing the incomes of the top 10% of the population with the total personal incomes of the rest of the population would show a much smaller rise in the relative size of incomes at the top.