Marriage can substitute for formal business contracts, especially in environments that lack a well-established system of contract or corporate law. In such settings, marriage can facilitate the efficient organization of labor and capital. In this paper, we explore the pooling of capital as an explicit motive for marriage. We measure the impact of a class of married women’s property acts introduced in the American South during the 1840s on assortative matching in the marriage market. These laws did not grant married women autonomy over their separate estate; they merely shielded their property from seizure by their husbands’ creditors. This had the dual effect of mitigating downside risk while restricting a husband’s ability to borrow against his wife’s property; it also preserved the bulk of the wife’s assets as inheritance for the couple’s children. Using a newly compiled database of linked marriage and census records, we show that these laws were associated with an overall increase in assortative mating, suggesting that the ability to pool capital importantly contributed to the gains from marriage. At the same time, there is considerable heterogeneity in the effect in different regions of the joint men’s and women’s wealth distribution. We provide an interpretation for these results.