Masayoshi Son’s SoftBank Group Corp. said Friday it will sell about ¥1.33 trillion ($12.5 billion) of the stock it holds in its Japanese wireless operation, adding to massive asset sales that have helped his conglomerate get back on track after missteps with startup investments.

The Tokyo-based parent said it will sell 927 million shares in SoftBank Corp. through a global secondary offering, about a third of its stake. The carrier’s stock, which closed at ¥1,431.5 on Friday, will be sold at a discount of 3 percent to 5 percent. Separately, the wireless unit said it will buy back up to 1.68 percent of its shares for about ¥100 billion.

Son, founder and chief executive officer, has turned around his company’s fortunes since March by selling off assets and repurchasing his own stock. The group had previously announced plans to sell about ¥4.5 trillion in assets and had said it was almost done with that program. Son has used the proceeds to pay down debt and embark on ¥2.5 trillion in buybacks.