The selloff in global markets is set to continue as a bear market takes hold "for a long period of time," according to widely followed investor Dennis Gartman, who warned investors not to go long on stocks.
"This is the start of a bear market," Gartman, the founder of the closely watched Gartman Letter, told CNBC Europe's "Squawk Box" on Thursday. "You stay in cash and you stay in short term bonds and you don't move out, this is a very difficult period of time and I'm afraid - and
I don't like to think about it – but this might be the very beginnings of a bear market that could last some period of time," he warned.
Gartman's comments come amid global market turmoil, particularly in the U.S. this week on the back of weaker economic data and fears of an economic slowdown in previous growth engines China, the U.S. and Germany.
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On Wednesday, yields on benchmark 10-year Treasurys hit their lowest level since May 2013 as investors scrambled for a safe haven for their cash as markets plunged; the Dow Jones Industrial Average closed down 173 points, or 1.06 percent, paring losses after an intraday decline of 458 points while other major indexes also recorded sharp falls and volatile trading.
Gartman warned that there was going to be "more than a mere 7 to 10 percent correction" in markets which had enjoyed a bull run since the U.S. Federal Reserve announced an unprecedented bond-buying program designed to stimulate growth in the world's largest economy.
"I don't like to be that way- you have to remember that in the business of trading…in the business of trading bears don't eat. Only bulls in the market enjoy the upside, only bulls actually get paid over time. I don't like to be bearish but this is a time to be at least neutral and perhaps at worst bearish."
Earlier this week, Gartman told CNBC he has "north of 80 percent in cash and short-term bond funds." He said Wednesday's flight to Treasurys was "real panic buying in the bond market probably by those that have been short, because so many people have been bearish of the bond market."
Current market turbulence has widely been attributed to a slowdown in economic growth, though Gartman was optimistic that economies were experiencing a slowdown rather than heading for recession.
"The global economy is not moving into recession, it's just slowing -- that's ok. Under those circumstances stock prices can tumble just a little bit more, we'll probably get down to a 15 percent decline across the board, across the world," he said.
"Probably in 6 months' time you'll probably hear me saying that I want to be a buyer of equities but in the interim, I think that safety is paramount and the side lines are better, I think cash is a wonderful investment and that's the place to be."
Gartman's comments were echoed by Michael Gallagher, director of research at IDEAglobal, who told CNBC on Thursday that concern over the "mediocre" global economy and the end of quantitative easing by the Federal Reserve could see the S & P 500 index drop another 100-points. "What this reflects is a correction after a very good bull market," he said.