CNBC
Charles Nenner
Nenner, who developed the "Nenner cycle," which he says can time the ups and downs of any market, said on CNBC that "for the next many years, you will not see the S&P more than 5% higher than [current levels.]"
But he warns this period of low returns will be followed years of large losses.
"And there's a major thing coming down - I'm talking about far in the future - a major collapse coming down starting in 2018 to 2020," he said.
Fortunately for investors looking for a long-term buy signal, Nenner sees the next bull market starting in 2020.
Earlier in the segment, Nenner had a contentious exchange with CNBC host Scott Wapner reminiscent of the exchange CNBC anchor Jackie DeAngelis had with Bill Fleckenstein earlier this month.
Wapner challenged Nenner regarding some of his past market calls, including a call back in 2010 for a "major crisis" after 2013 due to sunspot activity, and a 2009 call that the Dow would hit 5,000 in the next "two to two-and-a-half years."
Fortunately, those calls did not come to fruition.
Currently, Nenner said he is "totally" out of the market.
Nenner sees the primary catalyst for a crash being deflation, which he believes is already starting to take hold across the world's economies and cripple growth.
"I think the big problem is in deflation, which I'm saying every year," Nenner said.
"Europe is close to deflation, Japan is still in deflation, China has very low inflation, and if the dollar continues to rise in the United States, we'll get deflation over here. And I don't think investors are ready for it."
Nenner said that there is deflation in most of the world already, and that a strong dollar will see that deflation get exported here, making it hard for indebted governments to pay off their debts.
Below is the clip from Nenner's appearance on Tuesday. Unfortunately, Nenner's more contentious exchange with Wapner was not available from CNBC.