Chairman and CEO of Omega Advisors Leon Cooperman told CNBC on Wednesday he would take some profits on his holdings if stocks gained because the market is fully valued.
"I'm sympathetic to the idea that sometime in the next 12 to 24 months, there will be events that will catch the market. In other words, ... I think that inflation and interest rates will catch up to the market as we normalize," Cooperman said on "Squawk Box."
Cooperman — renowned on Wall Street for his value investing and fundamental analysis — argued that 2019 could be a turbulent year for equities because the Federal Reserve is tightening monetary conditions and inflation is looking stronger.
"I would be a reducer on strength, not a buyer on strength," he added. "I think if we get the 10-year [yield] over 3.5 percent that could be very competitive to the stock market. We're not there yet."
Between President Donald Trump's tax cut stimulus, a healthy labor market and the end of the Fed's historic quantitative easing policy, Cooperman said he wouldn't be surprised to see those issues "come to the fore."
Omega Advisors, which the hedge fund manager founded in 1991, has about $3.4 billion in assets under management, according to its website.
To be sure, Cooperman cautioned that while trouble could be ahead for late next year, he isn't ready to head to the exits just yet, saying "the conditions normally associated with a big decline are not yet present."
Cooperman told CNBC in May that while he may forecast trouble for the market next year, he still sees opportunities for value plays.
"The thing that keeps me coming back to the game every day, for 50 plus years, is in November I owned 5 million shares of Time Inc. It was actively trading at $10," he said at the time. "Nine days later, Meredith bought it for $18.50, cash."
"They tell me about efficiency. Sure the large-cap stocks are reasonably, efficiently valued, but there are so many things in the market that are not efficiently valued."
To illustrate his point, he noted in May that he added to his position in Facebook while the shares slumped earlier this year and said he had an open order to buy more of the social media company's stock at the $180 per share level. It's currently trading around $191.