The S&P 500 Is Flirting With 4200, Again. How to Know If This Rally Is Real.

The S&P 500 has rallied all the way back to just under the key 4200 level. That’s where the stock market gets dicey — and the index will need several factors to go in its favor for it to gain much past this point. 

The index is up almost 8% since hitting a March low point related to the recent banking problems. An initial driver of the rally was the stabilization of bank deposit outflows, easing fears of a substantial hit to the economy.