The Japanese conglomerate unveiled in March a 4.5 trillion yen plan to buy back shares and reduce debt. It has so far approved buybacks of two tranches of 500 billion yen each. In addition it announced a 500 billion yen buyback in March.
SoftBank said in a statement the 4.5 trillion yen programme had intended to be executed over four quarters from the time of the original announcement, but that it was possible the repurchase may not be completed until April 2021 or later.
Under the plan the group has been selling down core assets including stakes in Chinese ecommerce giant Alibaba Group Holding and U.S. wireless carrier T-Mobile US Inc.
SoftBank shares climbed as much as 2% following the announcement, with its share price up 43% year-to-date.
The highly leveraged group, a contrast to its cash laden Japanese peers, has repurchased 170 billion yen of its domestic unsecured corporate bonds.
With the proceeds from asset sales potentially more than its targeted amount, "excess funds are likely being considered for Vision Fund 2", wrote Kirk Boodry, analyst at Redex Research, in a note on the Smartkarma platform.
SoftBank has struggled to attract outside investment for a second fund after the poor performance of the first $100 billion fund, and has been investing in a limited capacity using its own money.
The fund can point to positive newsflow in recent weeks including the successful IPO of portfolio company Lemonade Inc, which listed in New York this month.
Goldman Sachs has placed a sell rating on the insurance startup saying it is facing years of losses before breaking even - a criticism that has plagued other SoftBank investments too.
($1 = 104.6700 yen)
By Sam Nussey