NBER Working Papers by Qingyuan Du

Motivated by recent empirical work, this paper formalizes a theory of competitive savings - an arms race in household savings for mating competition that is made more fierce by an increase in the male-to-female ratio in the pre-marital cohort. Relative to the empirical work, the theory can clarify a number of important questions: What determines the strength of the savings response by males (or households with a son)? Can women (or households with a daughter) dis-save? What are the conditions under which aggregate savings would go up in response to a higher sex ratio? While the theory can be best tested using data from countries with a sex ratio imbalance, the competitive saving motive is likely to be present and important in all countries.

Though the real exchange rate is a key price for most economies, our understanding of its determinants is still incomplete. This paper studies the implications of status competition in the marriage market for the real exchange rate. In theory, a rise in the sex ratio (increasing relative surplus of men) can generate a decline in the real exchange rate (RER) through both a savings channel and an effective labor supply channel. The effects can be quantitatively large if the biological desire for a marriage partner is strong. Empirically, we show that within China, those regions with a faster increase in the sex ratio also exhibit a faster decline in the RER (the relative price of nontradables). Furthermore, across countries, those with a high sex ratio tend to have a low real exchange rate, ...

Large savings and current account surpluses by China and other countries are said to be a contributor to the global current account imbalances and possibly to the recent global financial crisis. This paper proposes a theory of excess savings based on a major, albeit insufficiently recognized by macroeconomists, transformation in many of these societies, namely, a steady increase in the surplus of men relative to women. We construct an OLG model with two sexes and a desire to marry. We show conditions under which an intensified competition in the marriage market can induce men to raise their savings rate, and produce a rise in the aggregate savings and current account surplus. This effect is economically significant if the biological desire to have a partner of the opposite sex is strong. A...