This week, stock markets put investors on a stomach-churning roller-coaster ride. While uncertainty over China's economy has been widely cited as a catalyst behind the whipsaw action, one market strategist says the underlying problems in the U.S. are actually much deeper.

That, he predicts, will make it difficult to climb back to record highs by the end of this year.

"This is not just a China issue," Evercore ISI head of portfolio strategy research Dennis DeBusschere told CNBC's "Fast Money" this week, dismissing theories that China's devaluation of its currency, the yuan, was also the culprit.

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"This CNY devaluation is not the reason why the market has moved lower," DeBusschere added. "That's like blaming Lehman Brothers for the decline in stocks in 2008."

While DeBusschere conceded that China's surprise currency devaluation was the straw that broke the rally's back, he said there were a number of larger, long-trending domestic indications that signaled the bull run was in fact running out of steam. Among them, he said, is the fact that U.S. investors have been taking less risk onto their portfolios for the past year.

Riskier bets, he said, "have really been under pressure … and then it really accelerated to the downside following the CNY devaluation."