For years, AT&T (NYSE: T) and Verizon (NYSE: VZ) have had a very good thing going when it comes to data plans. Subscribers either bought too much data and paid for something they never used, or they did not buy enough and ended up paying the overage fees.
So last week, T-Mobile (NASDAQ: TMUS) announced its latest Un-Carrier initiative to fight such practices, with Sprint (NYSE: S) quickly following suit. As it turns out, the third and fourth place carriers see an advantage in unlimited data plans.