The merger of T-Mobile and MetroPCS is complete, and the combined company - T-Mobile US - started trading on the New York Stock Exchange this morning under the TMUS ticker.

T-Mobile and MetroPCS, however, will continue to operate as separate brands, led by Jim Alling on the T-Mobile side and Thomas Keys for MetroPCS. But they will migrate to a common network infrastructure and similar support functions.

T-Mobile chief John Legere will serve as president and CEO of the combined company, while former MetroPCS vice chairman and CFO, J. Braxton Carter, will now serve as T-Mobile US's CFO.

"The combination of T-Mobile and MetroPCS creates an even stronger disruptive force in the U.S. wireless market," Legere, who rang the opening bell at the NYSE this morning, said in a statement. "Together, as America's Un-carrier, we'll continue our legacy of marketplace innovation by tearing up the old playbook and rewriting the rules of wireless to benefit consumers."

MetroPCS and T-Mobile announced plans to merge in October. Under the deal, MetroPCS will make a cash payment of $1.5 billion to its shareholders for a 26 percent ownership in the combined company; Deutsche Telekom will own 74 percent.

The Federal Communications Commission approved the deal in March, one week after the Department of Justice did the same. It was also approved by the Committee on Foreign Investment in the United States, a necessary hurdle since T-Mobile is owned by a foreign company. More recently, MetroPCS shareholders gave the deal their stamp of approval.

T-Mobile recently launched its 4G LTE network in seven U.S. cities, and finally nabbed the iPhone, which it is offering on a non-contract basis as part of its bid to become the "un-carrier."

That "un-carrier" approach landed T-Mobile in hot water with the Washington state attorney general, who said the carrier's marketing for the program was deceptive. PCMag's Sascha Segan, however, begged to differ.

For more, see T-Mobile Cuts the Bulls**t, But Can it Win Customers?

UPDATE: PCMag spoke with T-Mobile this afternoon, and the carrier promised a massive set of LTE city launches, as well as HSPA+ phones for MetroPCS, coming over the next few months. Meanwhile, it appears there is an unexpected place you can get T-Mobile 4G LTE - in certain New York City subway stations.