e written down the value of their investments in Clearwire. The major MSOs purchased large swaths of valuable spectrum that cover 80 per- cent of the continental United States through their joint consortium, SpectrumCo, LLC. The consortium was formed to jointly invest in spectrum. Its current investors are Comcast, which owns 63 percent, Time Warner Cable with 31.2 percent, and Bright House Networks at 5.3 percent. The consortium purchased its spectrum at the 2006 FCC auction. Sprint Nextel and Cox sold their interests in the SpectrumCo consortium. Cox kept the spectrum that was in its own territory. Cox purchased additional spectrum in a 2008 FCC auction and used its spectrum to begin building out a mobile network. It offered Competition, Industry Structures, and Regulations service in three markets in 2009 and two more markets in early 2011. In May 2011, Cox announced that it was shutting down its mobile network and that it preferred to offer service on Sprint's network. The cable companies with spectrum that SpectrumCo won in the 2006 auction were required to build a network on the spectrum by November 29, 2021 or forfeit their rights to it. (FCC auctions specify dates by which bidders must build networks on the spectrum that they've been awarded.) In December 2011, Verizon Wireless announced that it had entered into an agree- ment with SpectrumCo to purchase its spectrum for $3.6 billion. SpectrumCo had paid $2.2 billion for the spectrum and thus will realize a profit of $1.4 billion if the FCC approves the purchase (as of this writing, the proposal is still being evaluated and mobile competitors are protesting that the sale will give Verizon an unfair advantage). As part of the agreement, they will sell each other's services. Verizon will sell the cable companies' broadband and TV services and the MSOs will sell Verizon Mobility services. If the spectrum sale is approved and the agreement implemented, MSOs will concentrate investments and expertise on TV and broadband services to residential and business cus