That means making sure your portfolio is balanced appropriately for your risk level, Duran said.
The market has already had one correction earlier this year. On Feb. 8, the Dow Jones industrial average, S&P 500 and Nasdaq all closed about 10 percent below record highs set Jan 26. It was the first pullback of that magnitude since 2016.
Duran isn't alone in warning about another drop in equities.
In March, Allianz CEO Oliver Bate said he expects a "more severe correction over the medium to long term" thanks to high market valuations and jittery investors. And after the correction in February, Morgan Stanley strategist Andrew Sheets said it was just an "appetizer, not the main course."
Duran said market declines typically happen when rates are going up, which is what happened in February. The move higher caused investors to fear the possibility that inflation was rising faster than expected.
On Thursday, the 10-year Treasury note yield broke above 2.9 percent, which is around the same level that sparked the earlier correction.
The market closed lower Thursday, with the Dow down 83 points and the S&P 500 declining 0.6 percent. The Nasdaq dropped 0.8 percent.
— CNBC's Fred Imbert contributed to this report.