Marriage and Taxes: What Can We Learn From Tax Returns Filed by Cohabiting Couples?

This paper analyzes the relationship between marriage and taxes by examining federal income tax returns filed by cohabiting couples. We use tax return data to estimate the tax consequences of marriage for cohabiting couples by comparing their tax liabilities from their separately filed returns to the tax they would owe if they were married and filed jointly. Under 2007 law, we determine that 48 percent of couples in our sample would have a marriage penalty and 38 percent would have a marriage bonus. We explain these results by examining the couples 'family characteristics and various components of the tax system.