The Japanese investment group had said in March that it planned to sell about $41 billion of assets, a move designed to pay down debt, bolster cash reserves and other things.
SoftBank said that it may sell some of its T-Mobile stake through private placements or public offerings. It said it could give no assurance that final deals will be reached.
Last month sources told Bloomberg that SoftBank was closing in on a deal to sell about $20 billion of its T-Mobile stake.
“These transactions may include one or more of: private placements or public offerings; privately negotiated transactions with T-Mobile or one or more stockholders of T-Mobile, including Deutsche Telekom, or third parties,” T-Mobile said in a Monday regulatory filing.
Separately, T-Mobile said Tuesday that texting and calling on the Bellevue, Wash., mobile carrier's network were again working following a major outage.
"Voice and text services are now restored. Thank you for your patience as we fixed the issues. We sincerely apologize for any and all inconveniences," said Neville Ray, T-Mobile's president of technology, in a tweet.
On social media and the site Downdetector, T-Mobile customers in the U.S. reported problems Monday with sending and receiving calls. The reports appear to have peaked at around noon Pacific Time.
T-Mobile CEO Mike Sievert said in a blog post late Monday that the outage was caused by an "IP traffic related issue that has created significant capacity issues in the network core."
T-Mobile shares at last check were off 0.7% at $103.99.