Then there is the GOP’s big addition to the tax code, which would add new complexity: a new, 25 percent rate for so-called “pass through” companies, which include everything from small businesses to hedge funds. Republicans argue that the rate will promote investment and increase economic growth, but it will also encourage high-income individuals to reclassify their income so they can take advantage of the 25 percent rate. Republicans crafted a complicated set of rules to block such tax avoidance, which will create new headaches for the 95 percent of businesses organized as pass throughs. “There will be complex rules in the code and then complex regulations and then complex struggles to enforce it,” said David Kamin, a tax expert at New York University who was an economic adviser to Barack Obama.
The same problem exists with the GOP plan to change how businesses’ overseas earnings are taxed. Under the current tax code, those earnings are not taxed until they are brought back into the U.S., leading to trillions of dollars of income kept offshore. Republicans want to move to a system where only domestic earnings are taxed. But this would create a huge incentive for businesses to shift their income so it appears as foreign income, requiring policymakers to create new rules to prevent such tax avoidance. “That will be a full employment act for international tax lawyers in the U.S.," said tax lawyer Libin Zhang.