JPMorgan's Marko Kolanovic, who accurately predicted would hit 2,300 on President Donald Trump's election win, now says another big event is about to happen—but this time, it has nothing to do with politics.



A sizable sell-off could be just weeks away, according to Kolanovic, who's the firm's head of quantitative and derivatives research. He puts the time frame between next month's Federal Reserve meeting and the June gathering.

"You could have a 5 percent pullback," he said Thursday on CNBC's "Fast Money."

Kolanovic, who's earned top honors from Institutional Investor, points to complacency and high leverage in the market as warning signs that a significant pause is likely. He finds that fewer investors are buying protection and positioning is "very stretched."

His latest assessment of the market comes as the Dow traded back above the key 20,000 level, with Friday being its best day of the year.