Born like China,growing like China

This paper studies the effects of China's one‐child policy on saving and foreign reserve accumulation. Fertility control increases the saving rate both by altering saving decisions at the household level, and by altering the demographic composition of the population at the aggregate level. I show that demographically induced changes in saving explain the build‐up of a large foreign surplus in China. As in Song, Storesletten, and Zilibtti (2011), the model features contractual and financial market imperfections. Government‐owned firms are less productive but have full access to the credit market. Entrepreneurial firms are more productive but face credit constraints. As labour switches from less productive to more productive firms, demand for domestic bank borrowing decreases. As saving increases while demand for loans decreases, domestic savings are invested abroad, generating a foreign surplus. The model predicts that China's foreign reserve accumulation will soon begin to slow down in response to recent relaxation of the one‐child policy.