The shift to mobile computing from traditional PCs has weakened Microsoft while empowering Apple, which makes the iPhone and iPad, and Google, which gives away the world's most popular mobile operating system, Android. Another $2.2 billion will be paid for a 10-year license to use Nokia's patents, with the option to extend it indefinitely. "[...] there are signs that (Microsoft) can innovate and successfully execute in the post-PC era, we expect the stock to languish at current levels," said Janney analysts Yun Kim and Alice Hur. Buying Nokia's phone business makes it unlikely that Microsoft would separate its struggling consumer business from its successful enterprise business, said Walter Pritchard of Citi Investment Research.