1.2.5 [related to the Economics in Practice on p. 330]

T-Mobile is the fourth-largest wireless communication provider in the United States, behind Verizon, AT&T, and Sprint. In an effort to differentiate themselves from their three larger competitors, T-Mobile was the first major company in the industry to allow customers to bring in unlocked phones to switch to their service, pay early termination fees for new customers that were switching service to T-Mobile, and promote the idea of customers not being tied down to a specific wireless provider. Do some research to find what has happened to the market share of each of these companies over the past several years, and describe how the other major wireless communication providers have reacted to these policies from T-Mobile.