Santoli: Will the bull be denied once again?

The peppy seven-week rally has carried stocks into the green for the year but also leaves them in a zone that has thwarted upside progress for more than a year.

While this market advance is sturdier and more energetic than the other bounces since last summer, the bulls face a fairly stiff burden of proof as stocks approach a point that has previously served as a decent selling opportunity.

The Standard & Poor's 500 index closed Friday at 2,072, up nearly 14 percent since the panicky Feb. 11 market low and a short hop from 2100 — a level that's presented an unusual amount of friction.

In the six months after the index first surmounted 2,100 in February 2015, it went on to cross that boundary on a remarkable 48 separate days over the next six months, or more than a third of all trading sessions. And the index never got more than a percent and half beyond 2,100, topping out with a close at 2,130 last May 21.

Not that there's anything inherently meaningful about the 2,100 value on the main U.S. equity benchmark. It's about one-third above where the prior bull market topped out in 2007, but that doesn't explain the stalling out of stocks there eight or more years later.