'This bull market has more legs'

Markets 'fairly valued': Pro

Stronger earnings for the second quarter and beyond will be the key driver that keeps gas in the bull market tank, leading quantitative strategists told CNBC on Tuesday.

U.S. stock futures turned higher in premarket trading, after Dow components Pfizer and Merck reporter better-than-expected second-quarter earnings.

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"[The market] is still doing better than most people expected. I think the same thing is true of the economy. I think the same thing is true of corporate earnings," said Ed Keon, portfolio manager at Prudential's Quantitative Management Associates. "The expectations are still relatively modest for the fundamentals. That means this bull market has more legs."

Savita Subramanian, head of U.S. equity and quantitative strategy at BofA Merrill Lynch, said in a "Squawk Box" interview the stock market is fairly valued. "If we are in that midcycle phase of the market, the multiple on the market should be a lot higher than where it is today."

The is up more than 7 percent this year. While Wall Street is coming off a cautious session Monday as investors await Wednesday's policy statement by the Federal Reserve, stocks are still trading around record highs.

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"My sense is that there are a lot of people waiting for a better entry point. There is a lot of cash sitting on the sidelines still. That means that better entry may get away from us," Subramanian said, pointing out that waiting and waiting during last year's 30 percent run was a costly strategy.

"We're not getting the kind of bump in valuations, the runup in valuations, if people were exuberant," Keon said. "Most of the people I talk to are nervous, worried, anxious. I think that is keeping prices in check and keeping expectations in check, and that means this bull market could go on for quite a while."

Quantitative analysts, or "quants" as they're often called, seek to understand the market by using complex mathematical and statistical modeling.

—By CNBC's Matthew J. Belvedere