Henrik Kleven (joint with Claus Thustrup Kreiner and Emmanuel Saez): ''The Optimal Taxation of Couples,'' forthcoming Econometrica

A paper by Henrik Kleven (joint with Claus Thustrup Kreiner and Emmanuel Saez) The Optimal Income Taxation of Couples is forthcoming in Econometrica.

This paper explores the optimal income taxation of couples, where each couple is modeled as a unitary agent supplying labor along two dimensions: the labor supply of a primary earner and the labor supply of a secondary earner. The authors show that, if second-earner labor force participation is a signal of the couple being better off (as when second-earner entry reflects high labor market opportunities), optimal tax schemes display positive tax rates on secondary earnings along with negative jointness whereby the tax rate on one person decreases with the earnings of the spouse. Conversely, if second-earner participation is a signal of the couple being worse off (as when second-earner entry reflects low home production ability), they obtain a negative tax rate on the secondary earner along with positive jointness: the second-earner subsidy is being phased out with primary earnings. These results imply that, in either case, the tax distortion on the secondary earner is declining in primary earnings, which is therefore a general property of an optimum. The authors also prove that the second-earner tax distortion tends to zero asymptotically as primary earnings become large.