Various market gurus warn that the current bull market is getting rather aged, and that a bear market is long overdue. A noteworthy exception is Jeff Saut, chief investment officer (CIO) at Raymond James Financial. "We ought to have another seven to eight years left," Saut told CNBC, noting that secular bull markets have a typical length of between 16 and 18 years. The current bull market is 9 years and 6 months old. Making reference to market history since World War II, he observed: "1949 to 1966: yes, there were pullbacks didn't stop the secular bull. '82 to 2000: yes, we had the crash in 1987. [It] didn't stop the secular bull market."

Stocks Since 2008 Financial Crisis 

Source: Yahoo Finance; gains computed from bear market low close on March 9, 2009 through the close on Sept. 12.

'Strong Fundamentals'

Another bullish note has been sounded by Joe Zidle, an investment strategist at The Blackstone Group, who predicts that the S&P 500 Index will break through the 3,000 level within the next few months, for gains of 3.8% from Sept. 12 and 12.2% from the start of 2018, per another CNBC report.

"What we have left for the rest of the year, I think, is going to be bullish with higher highs," Zidle told CNBC. He also observed, "Believe it or not, the best performance normally comes after a midterm election." In addition, he noted: "Fundamentals here are strong. Corporate balance sheets are good and earnings are improving." Zidle expects third and fourth-quarter earnings reports to be robust, and to bolster investor confidence. (For more, see also: 6 Stocks to Outperform the Late Bull Market.)

Rising Risks

Ray Dalio, the billionaire founder of hedge fund Bridgewater Associates, isn't exactly bearish right now, but advises investors to become "more defensive" in their equity investments, per the first CNBC report. He sees rising risks for investors, and believes that the current economic expansion is in its late stages, with only about 2 more years to run.

Art Hogan, the chief investment officer at B. Riley FBR, is worried about "policy mistakes, whether monetary policy that gets too aggressive at the wrong point in the cycle, fiscal policy that stimulates when we didn't expect it to and the third is trade policy," as he told CNBC. While Dalio believes that, so far at least, trade tensions are not "that big of a deal," Hogan said "I think it's going to be a drag on the global economy." (For more, see also: Why the US-China Trade War May Cause A Bear Market.)

'Widespread Inflation'

Despite his own near-term bullishness, Zidle raises a warning about inflation. "There's more inflation out there than people are pricing in," he told CNBC, adding: "Inflation is not strong, but it is very widespread. You can see it in oil and gas markets. You can see it in input prices." He believes that the yield on the 10-Year U.S. Treasury Note can reach 3.5% over the next 6 to 12 months, up by roughly 54 basis points from the Sept. 12 close. Rising bond yields, he noted, would exert downward pressure on stock prices.