TOKYO (Reuters) - Softbank Corp (9984.T) will issue $3.2 billion in corporate bonds, the biggest ever by a non-financial Japanese firm to retail investors, to convert part of the $17.7 billion in short-term loans used to purchase Sprint Nextel Corp (S.N) to longer term debt, two sources familiar with the matter said.
Softbank will issue the four-year bonds as early as March, the sources told Reuters on condition they not be identified.
Softbank, Japan's third-largest mobile carrier, agreed last year to buy a 70 percent stake in Sprint for $20.1 billion, in the biggest foreign acquisition by a Japanese company to date.
The Japanese firm borrowed from Mizuho Financial Group Inc (8411.T), Sumitomo Mitsui Financial Group (8316.T), Mitsubishi UFJ Financial Group (8306.T) and Deutsche Bank AG (DBKGn.DE) last December to fund most of the Sprint deal.
(Reporting by Emi Emoto and Reiji Murai; Writing by Mari Saito)