While a flat tax might deliver some tax savings to affluent taxpayers, financial advisor Cynthia Conger of Arkansas Financial Group in Little Rock says that it may be less than expected. “I have a few dual-doctor couples who are in the 36 percent bracket,” Conger notes. “But after deductions, their average rates are 23 to 26 percent. That’s not very far from the flat rate of 17 percent.” By contrast, those earning $90,000 would see their real tax rates—after deductions—increase from 13 percent to 17 percent. “This would increase taxes on lower- and middle-income people extraordinarily and hit them very hard,” she says. Meanwhile, affluent individuals would pay 6 to 9 percentage points less on their taxes.

Mark Watson, a tax specialist with Asset Management Advisors, a multifamily office in Palm Beach, Fla., thinks a flat tax could have a more wide-reaching effect. “If it reduces taxes for high-net-worth individuals, then you will see less interest in using tax shelters and other offshore investments,” he says. “You won’t have to use these tools because you won’t need them.” Watson says that any reform that includes permanent removal of the estate tax could represent a death knell for tax shelters. “I expect tax reform could significantly depress that industry,” he says.