Channing Smith, portfolio manager at Capital Advisors Growth Fund, told CNBC's "Power Lunch" on Monday that Apple is no longer the opportunity it once was. He is cutting his weighting from 5 percent to approximately 3 percent.

"We think it is at that mass adoption stage, and it's going to be tougher for Apple to grow," he said. "A lot of the purchases will be dependent on replacements and pricing will be a lot more difficult going forward."

Smith's main problem is that growth will be hard for a company with such a high level of market penetration, about 75 percent he says. He added that competitors such as Samsung could pose a real threat with its new phone model and version of Samsung Pay. "When you get to this size ... any type of advantage that you have quickly gets eroded away from competition," Smith said.

But it isn't only about growth. Smith isn't excited about the iWatch set to debut in April.

"We don't think the iWatch is going to be a category killer," he said. "And we don't really see the benefit of having one."

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Smith still thinks Apple is "a great company" but advises prudence in the future as growth becomes harder for the company to achieve.