T-Mobile Inc surprised Wall Street's quarterly revenue estimates early Thursday with more subscribers to its monthly plans, some of which come packaged with Netflix Inc service.

The third biggest wireless company in the United States in terms of subscriber base has been bracing for a court's verdict on whether the telco can move ahead with its $26.5 billion merger with Sprint Corp.

Many American states have filed charges against the two companies' merger, arguing that it is unfair, anti-competitive and will increase prices for subscribers.

T-Mobile's annual profits rallied to $11.9 billion from $11.44 billion, surpassing recent average estimates of analysts of $11.82 billion, IBES Data from Refinitiv, showed.

The US wireless carrier disclosed that it added 1 million new monthly postpaid subscribers. The latest figure was in line with projections from research agency, FactSet.

T-Mobile beat market estimates as regards the financials, with the firm posting $751 million in net income -- an increase from $640 million from the previous period.

With the exception of some items, T-Mobile earned 87 cents per share, which beat the 83 cents-analyst expectations. Revenues from the company also climbed to $11.88 billion, from $11.45 billion. This also beat average forecasts by New York traders. 

For most of the last two years, T-Mobile's agreement to buy Sprint has been in a holding term. In January this year, T-Mobile and Sprint delivered their closing arguments before the court regarding the merger. A decision this month is expected.

In December, T-Mobile unveiled their 5G networks, the next cellular generation. The telco stressed that its 5G infrastructure currently serves over 200 million people across the US.

The Justice Department approved the merger of the two wireless providers on condition that certain prepaid assets be sold off to Dish Network, making the satellite firm a fourth wireless entity. The Federal Trade Commission also approved the deal in 2019.

In its closing argument, T-Mobile maintained that customers will benefit from access to cheap, fast wireless speeds and that buying Sprint offers the best option for acquiring compatible spectrum required to boost its 5G systems.

Strong growth of T-Mobile contrasts sharply with that of Sprint, which has been sluggish of late, losing clients and earning less than market observers had anticipated. Sprint said it had 115,000 postpaid telephone subscribers in the last four months.

T-Mobile, on the other hand, pointed out that the company expects to add between 2.6 million to 3.6 million postpaid net subscribers in 2020, even without the merger deal with Sprint.