The upstart company that made the AT&T-mobile merger possible

MetroPCS, the upstart cellular company, is now poised to take over T-Mobile's spot as America's fourth largest carrier, has fundamentally changed the antitrust dynamic in the wireless industry.

MetroPCS founder and CEO Roger Linquist has long pursued a strategy of targeting markets with dense populations that are cheap to serve -- namely big cities. MetroPCS will make a roaming agreement to use a competitor's networks in a mid-tier city, but it doesn't open stores to offer local residents service, nor does it build its own towers there. That lets MetroPCS keep the large majority of its traffic on its own dirt-cheap urban network while Linquist lets others serve expensive suburban and rural communities. Net result: MetroPCS has rock-bottom costs and impressive profit margins. Last year it cost the company just $18.49 a month to provide wireless service to an average customer. (AT&T, Verizon and Sprint don't release comparable figures, perhaps because they would be much higher.) MetroPCS's low costs lets the company have healthy margins even as it underprices the rest of the market for service. MetroPCS's basic package of unlimited talk, text and Web runs $40 per month, and that's including taxes. AT&T cites MetroPCS and its smaller peer, Leap Wireless as key examples of robust competition.