After taking plenty of hits this year, Apple shares rose 2.5 percent on Wednesday. The boost comes after billionaire investor Carl Icahn tweeted about his firm's "large position" in the iPhone maker.

Apple shares have dipped more than 30 percent from a Sept. 2012 high of $705. Rumblings are rising over whether CEO Tim Cooks can innovate like the late Apple co-founder Steve Jobs. Earlier this week, Oracle CEO Larry Ellison made his views clear: Jobs is "irreplaceable" and Apple will have a hard time without him.

But Icahn is still betting on Apple. In fact, he sent a Twitter message noting he believes the company's stock is "undervalued." Icahn also tweeted about a recent meeting he had with Cook, among other things.

"Had a nice conversation with Tim Cook today. Discussed my opinion that a larger buyback should be done now. We plan to speak again shortly," he tweeted on Monday.

When Icahn Speaks . . .

Apple is clearly not at the top of its game. The iPad saw a lower-than-predicted shipment total of 14.6 million units in the second quarter, down from 19.5 million in the first quarter. The iPhone maker beat Wall Street expectations on shipping volumes but nevertheless posted a year-over-year decline in the second quarter.

Apple CEO Tim Cook said the company is "laser-focused and working hard on some amazing new products that we will introduce in the fall and across 2014." But it remains to be seen if he can come up with a cool new something to stop the bleeding.

We know that the iPhone 5S and other products are expected to debut Sept. 10 and should give Apple a much-needed bump. But how innovative the line up really is remains to be seen.

"Welcome to the undervalued Apple party, Mr. Icahn," David Rolfe, chief investment officer of Wedgewood Partners Inc., which has $5 billion under management, including Apple, told Bloomberg. "When Icahn says they can go further, they certainly can. Even in a slow-growth environment, Apple is still a prodigious cash-flow generator."

Who's Right?

We caught up with Ross Rubin, principal analyst at Reticle Research, to get his take on the shareholder activist Icahn's Apple moves. He told us the statements related to Carl Icahn's investment seem to indicate strong optimism regarding Apple's future.

"Larry Ellison's comment, in contrast, indicated pessimism. However, the management team at Apple and its overall market position is much different than the previous era before Steve Jobs returned to Apple. This calls into question the value of that time as an 'experiment' that would predict the company's future," Rubin said.

"The forthcoming Mac Pro desktop may not represent a new category or even a particularly strong revenue driver in Apple's overall mix, but it is a reminder that Apple can create a dramatic and striking reinterpretation of an existing product category," he said.