The global macroeconomic problem is quite simple

The coronavirus crisis and its impacts on behaviour will probably ex ante give rise to a global private sector savings surplus that is even larger than after the subprime crisis. Ex post , total savings and investment are equal at the global level. There are only two ways to move from the ex ante equilibrium (massive private savings surplus) to the ex post equilibrium (equality between total savings and investment): Either the global fiscal deficit becomes even larger than before the coronavirus crisis, absorbing the additional private savings surplus; Or the global real interest rate becomes even more negative than before the coronavirus crisis, to stimulate investment and, through rising asset prices and wealth effects, stimulate consumption. As after the subprime crisis, both solutions will probably be used after the coronavirus crisis.