household level, the PSF data provide us with information at each survey date on the stock of savings of each household member, which allows us to focus on wives’ savings and resource allocation decisions.

We implement a two-step analysis, detailed in the Empirical Approach and Identification Strategy section. In the first step, we obtain for each union the predicted risk of polygamy with a duration model. Identification in the second step relies on the different time patterns of transitions of unions to polygamy depending on the polygamy of the husband’s father. We thus make the assumption that the polygamy of the husband’s father does not affect the variation of saving behaviors over time other than through the risk of polygamy. Potential violations of this assumption caused by differential inheritance rules across groups or polygamy of the husband’s father partly capturing household wealth are investigated and ruled out in the Empirical Approach and Identification Strategy section.

Our main results show that the risk of polygamy has a positive impact on wife savings, but only on savings entrusted to formal or informal institutions, as opposed to savings kept at home, especially for women living in the poorest households. Household food expenditures are found to decrease with the risk of polygamy, suggesting a possible reallocation of women’s resources from food consumption to savings. In addition, women facing a larger increase in their risk of polygamy spend more on the education of their children, but this increase in education expenditures is exclusively funded by a higher contribution of their husband, while their own contribution decreases. They are also found to transfer more to their social networks. These results suggest that the risk of polygamy leads monogamous wives to engage in self-protective strategies by investing in assets that are out of the reach of their husbands and in their social networks. On the other hand, the risk of polygamy is not found to affect women’s labor market participation. By contrast, the risk of polygamy is positively correlated with monogamous husbands’ labor market participation and income, consistent with an accumulation strategy to afford a second wife.

This paper first contributes to the empirical literature on polygamy initiated by Grossbard (1976).<sup>2</sup> While the theoretical framework provided by Grossbard (1980), based on the theory of marriage developed by Becker (1974), accounts for the emergence and persistence of polygamy at the society level, little is known yet on the microdeterminants of polygamy. Indeed, most research in this area is based on the comparison of two groups of individuals according to the type of their union and does not account for self-selection effects. Jacoby (1995) goes further by identifying the causal relationship between female agricultural productivity and polygamy. However, these findings cannot account for the persistence of polygamy in urban areas, as observed in Senegal (Antoine 2002). Controlling for socioeconomic characteristics of both spouses, we find evidence of the transmission of norms regarding polygamy from fathers to sons. In this strand of literature exploring the microdeterminants of polygamy, the approach of this paper is original since we focus on unions and explore the determinants of the transition from monogamy to polygamy based on a survival analysis. Indeed, even in countries where polygamy is the norm, a non-negligible proportion of unions will remain monogamous.

> 2 See also Grossbard (2014) for a review.

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