With the S&P 500 up 10% for the year -- and nearly 50% from its March low -- the ongoing "buying stampede" means investors need to take a more cautious approach to equities, these brokerage experts say.

Who's Talking: Larry Adam, chief investment strategist, Deutsche Bank Private Wealth Management

The Gist: "While improving economic conditions support the recent rally and support our long-term positive view on equities, there are several technical and fundamental factors that suggest near-term headwinds," Adam writes.

On a fundamental level, stocks are no longer dirt cheap, Adam says. The market's trailing price/earnings multiple has expanded to 16 from a trough of 9.7 on November 20 of last year.

"As a result, further sustainable upside will be dependent on positive earnings growth, not just 'less bad' earnings," he says. Despite better-than-expected earnings (more than 70% of companies have exceeded estimates so far this season, according to Thomson Reuters), sales continue to be weak, he writes.

On a technical level, the so-called Relative Strength Index has notched it highest reading since early May of 2007, suggesting that the market is overbought, says Adam.

That leaves Adam cautious on equities in the near term, but there are reasons for optimism farther out. For one thing, positive earnings growth is expected to occur in the fourth quarter, which should provide a more sustainable upside for stocks.

Additionally, gross domestic product appears to have bottomed, and "expectations continue to build that the economy will begin to stabilize and rebound slightly during [the second half of the year] due to pent-up demand, re-stocking and a rebound in consumer confidence," he says.

Who's Talking: Jeffrey Saut, chief investment strategist, Raymond James

The Gist: If past market behavior is any indication, the current "buying stampede" is getting closer to the end than the beginning, Saut says.

"The typical stampede lasts 17 to 25 sessions, with only one- to three-day pauses/corrections, before they exhaust themselves on the upside," he writes, noting that Monday marked session 16 of that run.

Rather than try to pick the top, Saut recommends that investors use a short-term moving average to lock in some gains. "One of the tricks we have learned is to use a short-term moving average, like the 10-day moving average, and wait for the index to close below it before reducing positions," Saut writes.

That leaves plenty of opportunities for taking some profit in equities, especially given that close to 90% of stocks in the S&P 500 are above their longer 50- and 200-day moving averages, meaning that they are technically overbought.

Interestingly, the S&P 500 appears to be replaying a pattern it followed in 2003, where it bottomed in March and rallied into June, Saut says. "From there it flopped/chopped for awhile and then broke out above those June 2003 'highs' and tacked on another 15%," he writes.

And, like now, the first leg of that rally was driven by liquidity and the second by improving fundamentals and earnings, Saut adds.