Motorola Mobility Holdings Inc. (NYSE: MMI) shares remain skyward 55% today over Friday’s close after Google Inc. (Nasdaq: GOOG) said it would buy the cellphone business for about $12.5 billion, or $40 a share. Monday after the deal was announced, volume for Motorola ballooned to 54.4 million shares from a daily average of 4.3 million.

A release published August 15 noted that the acquisition of Motorola Mobility, a dedicated Android partner, will enable Google to supercharge the Android ecosystem and will enhance competition in mobile computing. Motorola Mobility will remain a licensee of Android and Android will remain open. Google will run Motorola Mobility as a separate business.

Larry Page, CEO of Google, was quoted in the release as saying, “Motorola Mobility’s total commitment to Android has created a natural fit for our two companies. Together, we will create amazing user experiences that supercharge the entire Android ecosystem for the benefit of consumers, partners and developers. I look forward to welcoming Motorolans to our family of Googlers.”

In the same release, Sanjay Jha, CEO of Motorola Mobility, said, “This transaction offers significant value for Motorola Mobility’s stockholders and provides compelling new opportunities for our employees, customers, and partners around the world.

“We have shared a productive partnership with Google to advance the Android platform, and now through this combination we will be able to do even more to innovate and deliver outstanding mobility solutions across our mobile devices and home businesses.”

Motorola Mobility Holdings, Inc. fuses innovative technology with human insights to create experiences that simplify, connect and enrich people’s lives. Its portfolio includes converged mobile devices such as smartphones and tablets; wireless accessories; end-to-end video and data delivery; and management solutions, including set-tops and data-access devices