Stocks mostly fell on Thursday.
The Shanghai Composite Index tumbled 1.6 percent, the STOXX Europe 600 fell 1.5 percent but the S&P 500 recovered from early losses to finish little-changed.
The S&P 500 is down 0.7 percent for the week, its first weekly decline in six.
If David Stockman is right, however, stocks are in for a steep and treacherous decline.
"As soon as the markets realize that the Fed and the ECB are out of ammunition, it's over," Stockman told CNBC. "Global deflation is going to turn into a recession worldwide."
Indeed, in Japan, consumer prices were unchanged in February, the tenth consecutive month that inflation has been around zero despite the Bank of Japan’s adoption in January of a negative interest rate alongside its already unprecedented asset purchases.