(Reuters) - Sprint Corp on Tuesday reported deeper losses than feared of monthly phone subscribers despite discount offerings, raising concerns that the wireless carrier may not be sustainable if its pending merger with T-Mobile is not approved.

FILE PHOTO: A woman walks past a Sprint store in New York City, U.S., April 27, 2018. REUTERS/Brendan McDermid/File Photo

Sprint said it lost a net 189,000 phone subscribers during its fiscal fourth quarter. Analysts were expecting a net loss of 117,000, according to research firm FactSet. Sprint shares fell more than 4 percent in extended trade.

The U.S. telecommunications firm, which is backed by Japan’s Softbank, also reported a worse-than-expected quarterly loss of 4 cents per share. Analysts were expecting a loss of 1 cent per share, according to IBES data from Refinitiv.

“Sprint won’t survive as a stand-alone company with their current capital structure,” said Jonathan Chaplin, analyst at New Street Research.

“If the T-Mobile acquisition is blocked, Sprint will need to find another deal. If they can’t find another deal they will likely need to restructure sooner or later. I have a hard time imagining anyone wanting to buy Sprint.”

Sprint and T-Mobile U.S. Inc are awaiting regulatory approval on their planned $26 billion merger, which is expected to help Sprint boost its investments in 5G, the next generation of wireless, and shed the negative perception of its network quality.

Last month, the two companies extended the deadline for completing their proposed deal to July 29 as the U.S. Justice Department’s Antitrust Division chief said he had not decided whether to approve the transaction.

Sprint, in a filing with the Federal Communications Commission on April 15, warned it is unlikely to play a meaningful competitive role as a standalone company in the years to come.

Sprint’s total net operating revenue rose 4.4 percent to $8.44 billion in the fiscal fourth quarter ended March 31, up from $8.08 billion a year ago. Analysts had expected revenue of $8.21 billion.

Sprint, in a post-earnings call with earnings, declined to provide a full-year outlook for fiscal 2019 because it is in the late stage of its merger with T-Mobile.

Sprint’s shares had closed up 0.9 percent at $5.79 in regular trade ahead of the results.

T-Mobile and Sprint are the No. 3 and No. 4 wireless carriers, respectively, in the United States behind Verizon Communications and AT&T.