“The CBO estimated that gay marriage in all 50 states would increase tax receipts by about $400 million a year if the George W. Bush tax cuts were extended and by about $700 million a year if they were not. Because those tax cuts ended up being mostly extended, the answer is probably somewhere in the middle, but closer to $400 million. The added revenue comes from the ‘marriage penalty’: Two-earner married couples where each spouse has a similar income tend to be taxed more heavily than they would be if both partners were single.”
