Internet investor Softbank Corp. said Thursday its U.S. unit has sold part of its stake in Internet portal Yahoo Inc. of the United States to reduce Softbank's interest-bearing debts and expand the group's broadband operations.

The selloff of 17.5 million Yahoo shares, worth $294 million, was made by Softbank America Inc., a wholly owned unit of the Tokyo-based firm, it said.

This lowered Softbank America's stake in Yahoo to about 4 percent from around 7 percent, Softbank said.

Following the share sale, Softbank will book 26.1 billion yen in capital gains for its earnings, it said.

Previously, Softbank America held about 37 percent of Yahoo shares at its peak period.