The has already seen fireworks this month.
The benchmark index was sitting at records Tuesday after surging to begin the week to net a new all-time high.
One number could determine whether this rally is for real, but it's not the one most pundits are watching, says Miller Tabak equity strategist Matt Maley.
"A lot of people are focused on the 3,000 level which is human nature, it's a big round number," Maley told CNBC's "Trading Nation" on Monday. "But, the most important thing to look for is can it get a more meaningful break. ... It's nosed above to new highs on several different occasions in the last 18 months. But, each time it's kind of rolled back over."
"Right now we need more than a 2% breakout like we've seen in the last couple of times. We need something more in the 3% range and that takes us up to about 3,030 so that's kind of the level I'm looking at," said Maley.
The S&P 500 would need to rally 2% to reach 3,030. If it reached that level by year's end, it will have surged 21% in 2019.
"We have the economy weakening a little bit, earnings growth full-year estimates are less than 3% now, we're going to need a kind of prove-me, a show-me [move], and get a more meaningful breakout to show that this market can really move a lot higher," said Maley.
Chad Morganlander, portfolio manager at Washington Crossing Advisors, said stocks should continue to climb with the fundamentals remaining strong.
"We believe that equities at this point do remain well supported. You have a U.S. economic backdrop that is continuing to improve, albeit at a more decelerating rate of 2% to 2.25%. That supports the earnings as well as revenue expectations for the S&P 500 going into 2020," Morganlander said during the same segment.
However, it pays to be selective and to avoid the riskier areas of the market that drove the S&P 500 to these gains, he added.
"We are recommending high-quality investment. Investors should look at sectors like consumer staples and health care and perhaps pare back the more volatile investments at this point," said Morganlander. "Overall, we think that the market could melt a bit higher over the next three to four months."
Consumer staples and health care have underperformed the market so far this year, gaining 15% and 8%, respectively, as the S&P 500 climbed 18%.