While the Standard & Poor's 500 Index has jumped 6.5 percent from its Feb. 5 low, the market still faces a risk of heightened volatility, says Gary Thayer, chief macro strategist at Wells Fargo Advisors.

"Investors now appear to favor defensive sectors rather than cyclical sectors," he writes in an article for Barron's. "This suggests that investors are cautious. Consequently, sentiment is still probably fragile, and the risk of an increase in market volatility persists."

To be sure, Wells Fargo remains bullish on U.S. stocks and the economy for the long term, Thayer states. "The U.S. stock market remains in an upward trend."

Editor’s Note: 18.79% Annual Returns . . . for Life?

Last year, cyclical stock sectors, especially consumer discretionary, outperformed defensive sectors, particularly utilities, he explains.

"However, investor sentiment is more cautious now, and the utility sector has done better than the consumer discretionary sector all but a few days this year."

Another defensive sector, healthcare, is outgaining the stock market as a whole, despite all the problems surrounding Obamacare, Thayer notes.

"This is probably because a lot of the stocks in the healthcare sector are domestic oriented" and thus don't suffer from slow global economic growth, he writes.

Others too say stocks may endure high volatility in coming sessions.

"Given the prevailing economic uncertainty, the likelihood of continued Fed tapering and a still-fragile environment in emerging markets, we expect the relatively higher levels of equity market volatility to persist," Russ Koesterich, chief investment strategist for BlackRock, writes in a commentary obtained by MarketWatch.

Editor’s Note: 18.79% Annual Returns . . . for Life?

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