Softbank, the parent company of Sprint, is ready to open talks once more on a possible merger between rival companies Sprint and T-Mobile. The Japan-based company is reportedly interested in selling its network carrier to Deutsche Telekom, T-Mobile's parent company.

The SoftBank Group is supposedly frustrated with the slow growth of Sprint in the United States. Mac Rumors reported that Softbank is willing to hand the control of Sprint over to its competitor though it will still have a minority stake in T-Mobile if the deal pushes through.

According to Reuters, the merger was supposed to have happened two and a half years ago before the deal fell through due to pressure from U.S. antitrust regulators. SoftBank was in talks with Deutsche Telekom with the intention of acquiring T-Mobile for the amount of $20 billion and merging it with Sprint. At the time, Sprint was worth more than T-Mobile. Back in 2014, the former's market value was around $36 billion while the latter was worth $30 billion. T-Mobile has since overtaken Sprint for the third spot on the list for most subscribers among the major wireless network carriers. T-Mobile also shot up its market value to about $50 billion while Sprint stayed on the $36 billion range.

Deutsche Telekom also stressed that it is no longer interested in selling T-Mobile which is another reason why Softbank is now looking at selling instead of buying. Nothing is currently happening, however, as anti-collusion rules set by the U.S. Federal Communications Commission prevent rival companies from having negotiations during a spectrum auction. The auction will end on Mar. 30 after which the two companies are expected to begin talks.

The news comes as a bit of surprise considering Sprint just announced yesterday that it is upgrading its unlimited data plan. The move was done in an effort to outdo the three other major carriers, which includes T-Mobile, that are currently embroiled in the so-called Carrier Wars.