Softbank Corp., the wireless carrier run by billionaire Masayoshi Son, will raise ¥300 billion ($2.9 billion) in a fresh bond issue to repay past debt, boost liquidity and make investments.

Softbank will offer five-year notes to individual investors, it said in a filing Thursday to the Finance Ministry. The price of the issue will be decided May 16, and there will be nine underwriters, including Nomura Securities Co. and Daiwa Securities Co., the filing said.

"The bond issuance is aimed at increasing our cash reserves so that we will be able to move swiftly when we make an investment in the future," Hiroe Kotera, a spokeswoman for Softbank in Tokyo, said by phone. "We don't have a specific target for investment at this point."

Softbank acquired Sprint Corp. for $22 billion last year and is mulling a bid for T-Mobile U.S. Inc. The firm sold ¥820 billion in domestic bonds last year — equal to almost 10 percent of all bonds offered in Japan in the period, data compiled by Bloomberg showed.

Softbank offered ¥400 billion in five-year notes with a coupon of 1.74 percent in June 2013. Maturing next month are ¥30 billion of 0.65 percent three-year notes and ¥14.9 billion of 4.36 percent seven-year securities, the data said.

Sprint, 80 percent owned by Son's firm, plans to proceed with the T-Mobile U.S. Inc. bid.