SoftBank shares were down 11.2% in morning trade, on track for their biggest one-day loss in more than 2-1/2 years.

Analysts said, however, that the share price slide was in part a pullback from a steep rally that had been driven by hopes of more share buybacks. As of Friday's close, SoftBank shares had gained more than 40% since October.

"Various expectations including another round of share buy-backs had pushed their share prices higher, and now they are in an adjustment phase," SBI Securities analyst Shinji Moriyuki said.

SoftBank did not announce a new share repurchase programme on Friday.

The Vision Fund logged investment losses of 1.38 trillion yen ($9.9 billion) in the three months to Sept. 30 as the value of its portfolio continued to slide.

But SoftBank as a whole reported its first quarterly profit in three quarters, buoyed by paring some of its stake in China's Alibaba Group Holdings.

($1 = 138.9900 yen)

(Reporting by Kiyoshi Takenaka; Editing by David Dolan and Edwina Gibbs)