A $40 Billion Wireless Sector Meltdown Puts Focus on T-Mobile

AT&T Inc. and Verizon Communications Inc. shocked investors with their second-quarter results last week — the former warning about the high cost of phone giveaways and the latter failing to meet growth targets.

The news sparked a sell-off that erased some $40 billion in market value from the three industry leaders. Now T-Mobile US Inc. is cast as the potential Goldilocks in this drama — if its second-quarter results are just right.