Global stocks have been rallying in recent weeks, climbing a “wall of worry” and confounding the bears, leading a number of strategists to warn the gains are unlikely to last and investors should remain cautious.

Photo: Oliver Quillia for CNBC.com

“I think we’re in choppy waters and that continues. You’ve got to remember to sell if you own the stock market now,” Charlie Morris, Head of Absolute Return at HSBC Global Asset Management told CNBC Europe’s “Squawk Box” on Wednesday.

Morris says with bad news on the global economy over the past year, the market had “tried to collapse”, but with so many people short stocks, the conditions hadn’t been ripe. That, he says, could change after the current rally ends.

“You need to trip the market to have a proper collapse. So you almost need to set it up with a rally, get everyone excited and then it can fall,” Morris said. “If there are risks, the risks to a very negative market come after this rally fades.”