AT&T may be one of the biggest mobile carriers in the United States, but few big companies stay big by not reacting to market conditions and working within said conditions to take advantage of new opportunities. With T-Mobile (News - Alert) recently making some big moves in the mobile carrier field, AT&T is bringing out a few big guns of its own, including some hefty new credits for those who make the jump from T-Mobile to AT&T.

More specifically, AT&T announced late last week that, starting January 3, customers who make the jump from T-Mobile to AT&T can expect some hefty new bonuses for making the change, including the option to trade in a current phone for a new one with AT&T—that alone will net users up to $250—as well as the ability to net $200 in credit for every line that's transferred from T-Mobile to AT&T with an AT&T NextSM plan, and either buy a new device or activate a device that's currently owned.

T-Mobile has boasted quite a bit in the way of change recently, not only matching the bigger companies by offering the iPhone (News - Alert) line in its mobile device selection, but also offering a new program that allows for more frequent upgrades to mobile phones in the various plans. The “un-carrier” concept seems to be working well for T-Mobile, and that's not good news in the halls of AT&T, who had once planned to buy T-Mobile. T-Mobile actually offered something in the way of rebuttal to AT&T's plan, calling it a “desperate move on the heels of what must have been a terrible Q4 and holiday for them,” according to T-Mobile CEO John Legere. Legere further promised some new “pain points” would be eliminated, and that more information about said pain points would emerge at CES (News - Alert) 2014.

As good as this looks for T-Mobile—when a bigger firm like AT&T is specifically reacting to events that a smaller company is putting out in the market, the smaller firm has to be doing something right—there's still something of an issue going on for T-Mobile. Reports have suggested that parent company Deutsche Telekom (News - Alert) is looking to get out of doing business in the United States, which may well leave T-Mobile ultimately on the selling block. As noted earlier, AT&T tried—and failed—to make its own bid for T-Mobile, but reports suggest that Sprint is looking to make that particular deal itself. That's not a bad move for Sprint (News - Alert), being by some reports the third largest carrier around. Picking up T-Mobile would give Sprint a major advantage against AT&T and Verizon, especially given how AT&T seems to be reacting to T-Mobile.

What's particularly interesting about this point, however, is some of the commentary that's getting involved. Some current AT&T customers, at last report, are starting to feel like second-class citizens, with AT&T diligently seeking new business, yet not extending much in the way of reason for current customers to stick around. That may be a flaw that AT&T should look to address; it's one thing to get new business, it's another—and altogether more difficult—thing to keep old business happy.

If Deutsche Telekom does depart the U.S market, and if Sprint lands T-Mobile, that could spell trouble for AT&T; it's already reacting to what T-Mobile does in the market, and if Sprint has that kind of support on its side, Sprint could make a move up. Only time will tell just where this all goes, but it could mean some big changes ahead on the mobile carrier field.