For dividend investors, a worst-case scenario for the wealthiest Americans would be that the upper income tax rate is returned to 39.6 percent, and dividends could then be taxed at that much higher rate, if the Bush tax cuts are left to expire.

 For individuals earning $200,000 and couples earning $250,000, there is also the new 3.8 percent tax rate that comes as part of the Affordable Care Act on certain types of income, including dividends, capital gains and rental income. (Read More: 'Fiscal Cliff'—What Are the Options for a Deal?)

In that case, dividends could be taxed at a steep 43.4 percent for the upper income bracket, and capital gains would be at 23.8 percent for the top rate, if the Bush tax cuts expire without change. Even if the tax cuts were maintained, dividends would be taxes at 18.8 percent for the richest Americans.

Sam Stovall, chief equity strategist at S&P Capital IQ, said dividend-paying stocks have been hit harder than most in recent weeks, in anticipation of higher dividend taxes in 2013, as well as a possible higher capital gains tax.