Sprint and T-Mobile have called off merger talks. The two carriers have been in talks for weeks, but were unable to come to an agreement on a combination. This marks the second time the third- and fourth-place wireless companies have walked away from the altar. It’s unclear why a deal couldn’t be reached.

“The prospect of combining with Sprint has been compelling for a variety of reasons, including the potential to create significant benefits for consumers and value for shareholders,”said T-Mobile President and CEO John Legere. “However, we have been clear all along that a deal with anyone will have to result in superior long-term value for T-Mobile’s shareholders compared to our outstanding stand-alone performance and track record.”

Sprint President and CEO and SoftBank Board member Marcelo Claure said in a statement that Sprint would continue to go it alone.

“While we couldn’t reach an agreement to combine our companies, we certainly recognize the benefits of scale through a potential combination,” Claure said. “However, we have agreed that it is best to move forward on our own.”