Home bias, the inclination of individuals to prefer to invest in their own country, given comparable foreign opportunities, of course, is only one of several decision-sets that determine how much a nation actually saves, as distinct from intended saving, and what part of that saving, or of foreign saving, is attracted to fund domestic investment.
Aside from the ex ante average inclination of the residents of a country toward home bias, the difference between domestic saving and domestic investment, that is, the current account balance, is determined by the potential rate of return on foreign investments relative to domestic investments as well as a nation's underlying propensity to save relative to that of other nations.