Is the world economy in a debt trap?

An alternative explanation for why real interest rates have fallen since the 1980s is that many countries have become less equal. Richer people save more as a percentage of their income, so as they earn a bigger slice of the economic pie, aggregate savings rise. Atif Mian, Ludwig Straub and Amir Sufi, three economists, say that the American economy suffers from a “savings glut of the rich”, two-thirds of which has been used to finance the debt of the American government or borrowing of other households.