Talks to merge the nation’s 3rd- and 4th-largest wireless operators have run into difficulties, according to multiple reports, with some even suggesting that the deal may not happen at all.

Japan’s Nikkei reported Monday that Sprint owner Softbank is backing out of talks to merge Sprint and T-Mobile. That account was corroborated by a Wall Street Journal report. However, CNBC followed up with a report that talks are still ongoing, but that both parties are struggling to come to an agreement over key issues.

At the center of the rift seems to be the question of who is going to control the combined entity, with both Softbank and T-Mobile’s German parent Deutsche Telekom insisting on being in the driver’s seat.

Sprint’s and T-Mobile’s stock both cratered after Nikkei’s initial report broke, and have only slightly recovered since.

Both telcos have been eyeing a potential merger for years. Talks of such a deal heated up last month, with reports indicating that the companies were close to agreeing to tentative terms.

A combined company would have more than 130 million wireless subscribers, allowing them to much more closely compete with AT&T and Verizon.

Previous reports indicated that a final announcement about the deal could come at the end of October, which could also indicate that these last-minute public quarrels may be part of final negotiations.