This piece was originally posted on Cato at Liberty

In a new column, Bruce Bartlett argues that U.S. corporate taxes are the lowest in the OECD, and therefore there is no need to reduce them. As usual, Bruce frames the debate as between sensible center-left economists like himself vs. crackpot Republicans. Yet on this issue, the great majority of serious tax scholars agree that a corporate tax rate cut is long overdue. Indeed, there is such broad agreement among experts that even the Obama White House is considering a corporate rate cut.

Bruce offers only weak and deceptive data in support of his views:

One would not know from the Republican document that corporate taxes are expected to raise just 1.3 percent of GDP in revenue this year, about a third of what it was in the 1950s.

This statistic does not show what Bruce pretends it shows. Corporate income taxes are paid by a subset of businesses called “C” corporations. But the share of total U.S. business income reported by C corporations has plunged in recent decades with the rise in other business structures, particularly LLCs and S corporations.

In a 2007 article in Tax Notes, PwC economist Peter Merrill showed that the share of total U.S. business income reported by C corporations fell from 71 percent in 1987 to just 49 percent by 2004. C corporations are less important business structures than they used to be, so it is to be expected that corporate taxes as a share of GDP has fallen.

Another way to see the relative decline in C corporations is to look at the ratio of C corporation revenues to GDP. In 1980, for example, C corporation revenues were more than two times larger than GDP ($6.1 trillion to $2.8 billion), but by 2008 C corporation revenues were only about 1.5 times larger than GDP ($22 trillion to $14 trillion). (Revenues from the IRS corporate report for those two years).

Bruce’s centerpiece is a table showing that U.S. corporate taxes as a share of GDP were 1.8 percent in 2008, a lower share than in other OECD countries. But the rise in LLCs and S corporations in the United States makes this table almost useless in furthering Bruce’s argument. C corporations may simply represent a smaller share of the overall economy in the United States than in other countries. To make his point, Bruce would need to show that taxes as a share of corporate profits are lower in the United States than elsewhere.

If taxes are low historically and in comparison with our global competitors, how are Republicans able to maintain that taxes are excessively high? They do so by ignoring the effective tax rate and concentrating solely on the statutory tax rate.

The effective tax rate Bruce refers to is the average effective rate, which is the rate he calculates in the faulty manner of taxes as a share of GDP. However, marginal effective rates are generally considered to be more important for international competitiveness. When Toyota is considering expanding its North American production at one of its U.S. or Canadian locations, it will look at the marginal effective tax rate in the two countries. And when it comes to marginal effective corporate tax rates, the United States has one of the highest rates in the world, according to a Cato study by tax scholars Jack Mintz and Duanjie Chen.

The economic importance of statutory tax rates is blown far out of proportion by Republicans looking for ways to make taxes look high when they are quite low.

Actually, statutory corporate tax rates are extremely important in the modern global economy because of the high mobility of corporate profits. In general, marginal effective tax rates drive real investment flows, but statutory corporate rates drive cross-border movements of reported income. Politicians frequently express their outrage at corporations pushing their profits offshore through transfer pricing and other techniques, but they could fix the problem anytime they wanted by slashing the uniquely high U.S. statutory corporate rate.   

This brings us back again to Bruce’s statistic that U.S. corporate taxes as a share of GDP are low at just 1.8 percent. Another reason that figure is low is that the high U.S. statutory rate is pushing reported income offshore through avoidance and evasion. If we cut the statutory corporate rate, the apparent low burden that Bruce points to would increase. This chart shows the inverse relationship between statutory corporate taxes and corporate taxes as a share of GDP.

By the way, if the importance of statutory corporate rates were “blown far out of proportion” as Bruce says, then why has every other advanced economy put so much effort into reducing its statutory rate over the last two decades? The answer is that liberal, centrist, and conservative governments around the world have understood that a country imposing a high statutory corporate rate shoots itself in the foot in today’s competitive world economy.

To sum up:

  • The U.S. has a low average effective corporate rate when measured incorrectly as a share of GDP, as Bruce does. The low rate results from the relative decline in C corporation business activity, the high U.S. statutory rate driving profits offshore, and the high U.S. marginal effective rate suppressing real investment.
  • The U.S. has one of the highest statutory corporate tax rates in the world. The high statutory rate drives reported income offshore, and it is also an important component of the marginal effective tax rate faced by companies.
  • The U.S. has one of the highest marginal effective corporate tax rates in the world according to some calculations, which likely reduces U.S. capital investment substantially. After all, “corporate taxes are the most harmful type of tax for economic growth,” according to the OECD.