Pointing to data showing run-ups in foreign purchases of U.S. stocks before the 1987 crash, the dot-com bubble in 2000, and the 2008 financial crisis, Ed Yardeni wrote in his eponymous research newsletter, "Their buying has a record of being a contrary indicator. They tend to be big buyers right before bear markets."

Investors are winding down another volatile week with U.S. stocks are pace to wrap a losing week. Federal Reserve Chairman Jerome Powell fired a warning over tariffs, on Thursday President Trump clapped back calling for Powell to cut rates.

Stocks are rallying worldwide Monday after President Donald Trump relaxed some of his tariffs, for now at least, and as stress from within the U.S. bond market seems to be easing. The S&P 500 was up 1.