The merger still needs to be approved by the US regulators who have in past taken a critical view of similar marriage between big corporations.
T-Mobile agreed on Sunday to acquire peer Sprint, in an all-stock deal that will combine the third and fourth largest US wireless carriers and is expected to attract regulatory scrutiny over its impact on consumers.
The agreement caps years-long talks between the companies, setting the stage for the creation of a carrier with 127 million customers that will be a more formidable competitor to the No.1 and No.2 wireless players, Verizon Communications and AT&T.
US regulators, which have challenged in court AT&T's $85 billion deal to buy US media company Time Warner, are expected to grill Sprint and T-Mobile on how they will price their combined wireless offerings.
Under the deal, T-Mobile majority-owner Deutsche Telekom AG will own 42 percent of the combined company, which will have a market value of over $80 billions, on its books.
Sprint's and T-Mobile's first round of merger talks ended unsuccessfully in 2014 after US President Barack Obama's administration expressed antitrust concerns about the deal.
T-Mobile has fared better than Sprint, even if it remains a distant third to Verizon and AT&T.
It has managed to score sustained market share gains, as innovative offerings, improving network performance and good customer service attract new customers, according to Moody’s Investors Service.
T-Mobile became the first major US carrier to eliminate two-year contracts, a shift quickly embraced by consumers and copied by competitors.
The company has also badgered rivals with its unlimited data plans.
Both Sprint and T-Mobile are far behind Verizon and AT&T in upgrading their network to accommodate next generation 5G wireless technology.
Even after their merger, the combined company's budget to invest in 5G will be smaller than Verizon or AT&T's.
However, Sprint and T-Mobile hope the deal will give them more firepower to participate in auction for spectrum to develop 5G.
They plan to participate in a spectrum auction in late fall.