The Standard & Poor’s 500 Index closed above the key psychological level of 1,500 for the first time in more than five years Friday, and that has some experts thinking the market might be ready for at least a pause.

"Fifteen hundred is a big level,” James Paulsen, chief investment strategist at Wells Capital Management, tells CNBC.

“This is where it died in 2000 and in 2007. … This is a decade in the making, and it's a pretty big round number," said.

Editor's Note: Billionaires Dump Stocks. Prepare for the Unthinkable.

Mark Luschini, chief investment strategist at Janney Montgomery, thinks excellent economic data or profit reports would be needed to push the index higher.

"I think the market could be setting up for a pullback. … You've come to the point where the market has borrowed on some of the good economic news," he tells CNBC.

To be sure, many experts don’t expect any correction to last long. David Bianco, chief U.S. equity strategist for Deutsche Bank, lifted his forecast for the S&P 500 Friday by 25 points to 1,600 for this year.

And Dan Greenhaus, chief global strategist at BTIG Strategy, predicts 1,650, The Wall Street Journal reports.

Some experts are impressed with individual investors’ return to stocks. “You’ve got a real sea change in investor outlook,” Andrew Wilkinson, chief economic strategist at Miller Tabak, tells The New York Times.

Editor's Note: Billionaires Dump Stocks. Prepare for the Unthinkable.