However, there's reason to doubt the market, too. The latest economic data showed construction spending fell 0.4 percent in September, below the 0.7 percent growth that had been expected.
Meanwhile, readings on manufacturing were mixed, with the Institute for Supply Management's index unexpectedly rising in October, while Markit's final reading showing its lowest rate of growth since July.
Looking forward, on CNBC's "Closing Bell" Sam Stovall of S&P Capital said he'd side with the bulls. "History says, but does not guarantee, we are likely going to see an advance of 5-8 percent on average (into year-end), before falling into another decline of 5 percent. So we could eclipse 2,100 before year end, but then see a digestion once again."
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Frank Braddock of JHS Capital Advisors shared the optimism. "At the end of the year, I think we'll be higher too," he said, also on Monday's "Closing Bell," citing relatively strong fundamentals
Looking at the bond market, Quincy Krosby of Prudential Financial also made the case for an advance. "The yield on the two-year is bumping up," she said. "That's the kind of move I expect to see when growth is coming into the economy."
"For the next 60 days, things are lining up nicely," added Jeff Reeves, InvestorPlace.com. He, too, is looking for S&P 2,100.