The Dow Jones Industrial Average hit a milestone last week when it crossed the 11,000-point mark Friday for the first time in 18 months.
The Dow is up nearly 68 percent from its 12-year closing low of 6,547.05 on March 9, 2009.
"The magnitude of this rally is directly correlated to the magnitude of the crash that preceded it," Dan Wantrobski, director of technical research at Janney Capital Markets, told the Wall Street Journal. "It's almost like reverse gravity."
The Dow last closed above 11,000 on Sept. 26, 2008, about 10 days after Lehman Brothers filed for bankruptcy.
The Dow opened this morning at 11,007, though it quickly fell below 11,000.