The agreement capped four years of on-and-off talks between the third and fourth largest U.S. wireless carriers, setting the stage for the creation of a company with 127 million customers that will be a more formidable competitor to the top two wireless players, Verizon Communications Inc (VZ.N) and AT&T Inc (T.N).

U.S. regulators, who have challenged in court AT&T’s $85 billion deal to buy U.S. media company Time Warner Inc (TWX.N), are expected to grill Sprint and T-Mobile on how they will price their combined wireless offerings.

Verizon has 116 million U.S. wireless customers, according to a spokesman, while AT&T has 93 million branded customers, as of the first quarter.

Their first round of merger talks ended unsuccessfully in 2014 after the administration of then-U.S. President Barack Obama expressed antitrust concerns.

The new deal will create the highest-capacity U.S. network, lower prices, create jobs and improve service in rural areas, said John Legere, the chief executive of T-Mobile and the new head of the proposed combined company.