Seven possible causes of the very low risk-free real interest rates in OECD countries

Real risk-free interest rates are currently very low in OECD countries, which, in principle, could be explained by seven mechanisms: A global rise in private savings and in demand for risk-free bonds; A decline in global investment needs; Low productivity gains; A low return on capital; A lack of inflation and expansionary monetary policies; A rise in risk aversion and a shift among investors into risk-free assets; Population ageing, which drives up per capita capital. All seven of these possible causes of low risk-free real interest rates seem to apply, with the exception of the fourth (low return on capital).