NEW YORK (TheStreet) -- Stocks have had a rough week, with the broader market closing lower in each of the past four trading sessions. However, that's not stopping Scott Wren, senior global equity strategist at Wells Fargo Investment Institute, from recommending that investors stay long on equities. 

In fact, too many investors aren't long enough. According to Wren, many investors have too much cash on the sidelines. Those investors should embrace volatility and use their extra cash to buy stocks on a deeper pullback. 

The current bull market still has momentum, as the economy continues to improve, he said. With annual returns of 6% to 10% expected for the next few years, buying today makes sense, he added. 

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Consumer confidence measures are also promising, as more Americans are feeling better about their financial situations and the economy as a whole. Gas prices are lower, 401(k) balances continue to trend higher, stocks are doing well, and the labor market is adding more jobs. 

However, Wren acknowledged that low wage growth is somewhat concerning and that earnings for the first quarter are likely to be disappointing. The strength of the U.S. dollar has forced many analysts to ratchet down earnings expectations for the first quarter and even for all of 2015. 

While Wren says some of the estimates have come down too much, volatility is still likely to increase around earnings season, which will create buying opportunities for long-term investors. 

The S&P 500 I:GSPC may pull back to around 2,010, near the 200-day moving average, but will likely find support near that level. 

As for when to buy, investors should consider buying part of their long position now and continuing to add to it throughout the decline, he concluded.

This article is commentary by an independent contributor. At the time of publication, the author held no positions in the stocks mentioned.