"Google is paying a premium price" for Motorola Mobility , he said. "They're buying this company to protect its Android franchise from patent threats, but we don't think there’s any guaranty that such a transaction will be able to help in that regard."
He is also concerned the combination of the two companies will take longer than Google expects, "degrading significantly Google’s growth and its margins."
Google "is in a variety of different areas and has competitors in almost all of them," he added. The company has "gotten a lot of great publicity with Google+ but we’ll see how that plays out. They are spending aggressively to stay ahead of the competition."
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Scott Kessler does not own stock and Standard & Poor's has no financial relationship with Google or Motorola Mobility.