Abstract
This paper investigates the internal financial decision-making process of households by employing a unique panel dataset containing the disaggregated wealth of the entire Swedish population over seven years. We directly estimate the outside options of spouses that determine their decision power and utilize a source of exogenous variation in sex-specific labor demand to show that its distribution among spouses is a driving force in the aggregation of spouses' preferences in financial decision making. As the decision power of female spouses grows, participation in the equity market decreases, participation in other risky asset markets increases, the share of wealth allocated to risky investments decreases, the riskiness of the portfolio decreases, and idiosyncratic risk decreases. We also study the effect of underdiversification on household welfare and find that women exert the in uence of their decision power to reduce the cost of underdiversification.