Hillary Clinton is proposing complex changes to the capital gains tax that will hit high-earners.

Clinton wants to have six capital gains tax rates for those in the wealthiest income tax bracket. For a single filer, that means the bracket includes those earning $411,500 a year. For married couples filing jointly, it means $464,850 a year. Assets sold within two years would be hit by a total 43.4 percent capital gains tax, with the rate falling for each additional year down to 23.8 percent for assets held for six years or more.

Ryan Ellis, tax policy director at Americans for Tax Reform, calls it "the most complex and Byzantine capital gains tax rate regime in history." Ellis adds, "By anyone's definition that's really stupid tax policy."

The tax gets even more complex when one considers those who aren't in the top income tax bracket. Taxpayers who hold their assets longer than a year might pay one of five rates, ranging from 0 to 23.8 percent.

Clinton's proposal marks a change in her position on capital gains since her last presidential campaign. "I wouldn't raise it above the 20% if I raised it at all," Clinton said in an April 2008 Democratic primary debate. At the time, the top capital gains tax rate was 15 percent, but it is now 23.8 percent.

Clinton says she's trying to fix the problem of corporations who care more about their quarterly earnings report than about long-term investments. "It won't even fix the perceived problem she purports to address," Ellis says. Corporations make decisions that will maximize shareholder value. They don't care how long shareholders hold onto stock, so tax reform that punishes short-term stock sales and rewards long-term investments will have little effect.