TOKYO (Reuters) - Japan's SoftBank Corp (>> Softbank Corp) said on Monday it plans to sell a 450 billion yen (3 billion pound) unsecured subordinated bond, mainly to retail investors, with proceeds earmarked for investment and to repay loans.

SoftBank, which paid $22 billion for U.S. carrier Sprint Corp (>> Sprint Corp) in 2013, is a prolific investor in telecoms and Internet firms. It has said it plans to invest $10 billion in India's potentially huge but underdeveloped online retail market.

SoftBank spokesman Mitsuhiro Kurano declined to comment further on how the proceeds will be used, but company finance manager Yoshimitsu Goto told Reuters in an interview this month they want to be prepared for any investment opportunity.

"If an investment opportunity were to suddenly appear tomorrow, we want to be financially prepared and not lose the opportunity due to the lack of money," Goto said.

The offering will carry a coupon of 2.5 percent and be rated BBB+ by Japan Credit Rating Agency, SoftBank said in a statement.

The underwriters are Nomura Securities Co, Daiwa Securities Co, Mizuho Securities Co, SMBC Nikko Securities Inc, Mitsubishi UFJ Morgan Stanley Securities Co, SBI Securities Co, IwaiCosmo Securities Co, Okasan Securities Co and Tokai Tokyo Securities Co, SoftBank said.

(Reporting by William Mallard, Teppei Kasai and Yoshiyasu Shida; Editing by Edwina Gibbs)

Stocks treated in this article : Softbank Corp, Sprint Corp