The absurdity of this claim is clearly revealed if one considers capital gains that accrue to short sellers, who pay rather than receive dividends while their positions are open. Following the logic of the argument, one would be forced to conclude that short sellers are taxed at an effective rate of negative 20%, thereby receiving a significant subsidy due to the existence of the corporate tax. The flaw in this reasoning is apparent when one recognizes that asset prices are lower (relative to the zero corporate tax benchmark) not only when a short position is covered, but also when it is entered

Economist’s View: Is Romney Double Taxed?

Rajiv Sethi looks at the numbers and concludes that Romney isn’t being double taxed and doesn’t have an effective rate of 45% to 50%.