'Fake news' and a $4 trillion swing: Inside the stock market's wild moves today

Desperate for some relief from the relentless three-day stock rout, investors sparked a momentary rally Monday apparently based on what turned out to be fake news.

The S&P 500 rallied 8.5% in 34 minutes midmorning, briefly adding $3.6 trillion in market value.

That was after it fell as much as 4.7% and officially entered bear market territory at the opening bell. At its intraday peak, the S&P 500 was up 3.4% for the day.