Why do some countries save more than others?

Some countries have the resources and capacity to save more than the other countries. This paper analyses the determinants of annual saving. The analysis uses the optimal saving function which is derived from the household inter-temporal utility maximisation. The predictions from the comparative statics are compared with micro survey data in Japan and the US. In addition, the preference of inter-temporal consumptions is estimated. These comparisons and estimations suggest that higher annual saving could be explained by higher income, lower interest rates, shorter saving spans, longer retirement spans, and higher preference for retirement-span consumption.