Well, that was fast.
The S&P 500 hit 1334 in morning trading Wednesday. You may not have inscribed that number on your forehead, but it is noteworthy all the same because it means the big-cap stock index has doubled its financial meltdown low of 666.79 on March 6, 2009.
That means the S&P took less than 23 months to rise 100% -- which appears to be its fastest double since S&P started publishing the index in 1957.
So much for all the talk two years ago that stocks might be good for a modest dead-cat bounce but little more.
“The scale of this rally is just enormous,” said New York money manager Barry Ritholtz. He calls it the most intense rally since the Depression.
Even during the go-go 1990s, the S&P typically took around three years to double. For instance, it first cleared 1,000 on Feb. 28, 1998 -- 35 months after its first move above 500 on March 24, 1995.
Barry Ritholtz, who runs Fusion IQ and writes the Big Picture blog, says we haven't seen anything like the 2009-2011 surge since the Great Depression bouncebacks of 1932 and 1935.
Ritholtz says the average stock market bounce following a crash is 70% or so, and is stretched over a longer period.
But of course, in previous cases the Fed wasn’t buying up half a year’s worth of Treasury issuance and holding short-term interest rates near zero.
“This one is unique,” said Ritholtz. “Obviously the Fed is the key difference. We have never seen them throw this much liquidity into the mix.”
Accordingly, most market observers are now tapping their feet waiting for the inevitable pullback. The average correction following a postcrash bounce is 25%, Ritholtz said.<!-- more -->
There are all sorts of reasons to expect the momentum to turn against stocks after their unprecedented gains. They range from rising bond yields and stretched stock valuations to political unrest in the Middle East and another iteration of the ongoing debt crisis in Europe.
Though the U.S. economy appears to be picking up steam, skeptics note that government spending is still a much bigger factor than usual -- a trend they say won’t go on too much longer as the austerity debate picks up in Congress.
But of course, even many of the forecasters who got the 2008 meltdown right have been premature with their calls for an end to this stock market rally. Ritholtz has been keeping a lot of cash around, though he says it’s not a foregone conclusion that we'll have a selloff soon.
All the same, there are some unnerving parallels to consider first. The only rallies that rank with the current one in terms of intensity were the 1932 and 1935 ones -- and stocks in those cases ended up "giving almost all of it back," Ritholtz said.
So it may not be time to run for cover -- but neither is it time to swing for the fences, let's say.
Also on Fortune.com: