Eventually the private sector will complete its balance sheet repairs and resume borrowing. When that happens, inflation can quickly spiral out of control unless the central bank drains the liquidity it pumped into the market under quantitative easing or helicopter money. For example, excess reserves created by the Fed currently amount to some 15 times the level of statutory reserves.

That implies that if businesses and households were to resume borrowing in earnest, the US money supply could balloon to 15 times its current size, sending inflation as high as 1,500%. The corresponding ratios are 28 times for Japan and Switzerland, five times for the eurozone, and 11 times for the UK.

Once private-sector demand for loans recovers in these countries, confidence in the dollar, euro, and yen will plummet unless the Fed reduces excess reserves to one-fifteenth of their current level, the ECB to one-fifth, and the Bank of Japan to one-twenty-eighth.