About 250,450 same-sex couples file joint tax returns in 2015, according to a new report from the Brookings Institute. Over the two previous years, the number of same-sex filers increased about 40 percent each year from about 131,080 filers in 2013 and 183,280 in 2014.
Changes in marriage laws are the main reason for the spike, researchers said. A 2013 Supreme Court invalidation of a key provision in the 1996 Defense of Marriage Act (Windsor v. U.S.) allowed same-sex couples to be treated as married for all federal tax purposes if they were legally married in a state where it was recognized. And in 2015, Obergefell v. Hodges made same-sex marriage the law of the land.
In “Same-sex married tax filers after Windsor and Obergefell,” available for download at brookings.edu, Brookings Senior Fellow Adam Looney, along with Robin Fisher and Geof Gee at the Treasury Department Office of Tax Analysis, examine data from jointly-filed tax returns to provide the first analysis of marriage patterns of same-sex couples in the years immediately following the significant Supreme Court rulings.
In general, overall rates of same-sex filing in 2015 were highest in states that had legalized same-sex marriage prior to 2013 or in 2013. In states that had not legalized same-sex marriage until 2015, rates were relatively lower up to and including the year 2015. The percentage increase in same-sex filing, however, was relatively high in those states.
When compared with different-sex couples filing jointly, the analysis reveals that same-sex joint filers are generally younger, higher income and less likely to claim dependent children. In 2015, 48 percent of different-sex couples claimed children as dependents, compared with 28 percent of female-female couples and just 7 percent of male-male couples. Same sex joint filers are also more likely to live in metropolitan areas and coastal states than different-sex filers.
The analysis examines where same sex couples live in several different ways: By using geographic areas defined by state, by regional labor markets (“commuting zones”) and in select large five-digit zip codes. Unsurprisingly, there are large differences in the number and share of same-sex couples filing in different states, with the highest proportion of same-sex filers living in coastal states, in certain metropolitan areas, and in states that had legalized same-sex marriage prior to 2013.
For the U.S. as a whole, same-sex filers made up only 0.48 percent of all joint filers in 2015, though the rates varied widely across the country. In D.C., for instance, which had some of the highest shares of male-male filers, same-sex couples accounted for approximately 4.2 percent of all married filers. States in the south and Midwest had the smallest shares of same-sex filers. In Mississippi and North Dakota, they made up just 0.2 percent of all filers.
In addition to geographic differences, the report also sheds light on pay disparities between same-sex couples and their different-sex peers and how the disparities differ depending on whether a couple is comprised of two men or two women.
To start with, the gap in average annual incomes of male-male couples and female-female couples is significant. When comparing the incomes of all joint-filers nationwide aged 25-55 in 2015, female-female couples earn about 68 percent of what male-male couples earn. That’s roughly 10 percentage points greater than the widely cited “pay gap,” that women earn on average 78 cents for every $1 men earn.
What about the gap between same-sex couples and their opposite-sex peers? For 2015 filers nationwide between the ages of 25-55, average household incomes for male same-sex couples was higher than household incomes of opposite-sex couples. Male-male couples earned about $168,233 and different-sex couples earned about $119,803. That’s a gain of about $48,000 for male-male couples. Meanwhile female-female couples made less than their opposite-sex peers — about $5,000 less. Female-female joint filers earned about $115,094.
But much of this can be explained by the concentration of same-sex couples in higher-income coastal states and metropolitan areas. When adjusting to account for location, the gap between the incomes of same-sex and different-sex couples shrinks for men, but grows for women. When comparing same-sex couples with different-sex couples in their own neighborhoods, the analysis reveals that while male-male couples still earn, on average, about $15,000 (or 10 percent) more than different-sex couples, female-female couples actually earn about $16,000 (12 percent) less than their different-sex neighbors.