Google searches for ways to please investors in 2015

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For Google bulls, 2015 could not come soon enough.

Last year wasn't pretty for fans of the search giant. The stock fell 5 percent, which was its worst performance since 2008. Google underperformed all the major U.S. averages.

So, what were the main concerns pressuring the stock and what's the outlook in 2015?

One big concern, say financial analysts covering the company, is that advertising dollars were moving away from Google and toward social networks such as Facebook.

That worry became more heightened when the company last reported earnings in October.

Paid clicks, which is a closely watched measure of how often users click on a search ad, increased just 17 percent. That missed Wall Street's expectations, and represented a sharp slowdown from the prior quarter.

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But other analysts say concern among investors is misplaced. They contend that Google is just growing off a much larger base than Facebook, which explains the difference in growth rates between the two rivals.

"We don't see any evidence that Facebook is stealing away ad dollars from Google," Mark Mahaney, a managing director at RBC Capital Markets, told CNBC. "We think they are both taking dollars from a larger ad pie."

Can Google make the mobile leap?
Can Google make the mobile leap?

Beyond its ad business, another real concern among investors is the amount of money Google is spending to move into new markets. Analysts at Janney Capital Markets think Google's spending on capital expenditures could jump 50 percent to $11 billion in its current fiscal year.

The question is whether that spending spree, on everything from wearables to connected cars, will ultimately pay off for the tech titan.

"Those are all very large opportunities," Mahaney said. "Do they get them all right? Probably not but, if they get two or three of those right, then that can help sustain these growth rates for much longer than the market realizes."

Finally, one year doesn't necessarily make a trend. While Google did suffer a tough 2014, the stock has been a long-term winner. Since its IPO in August 2004, Google is up more than 1,000 percent.

Google did not respond to a request for comment.

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