Softbank Corp. had its debt rating raised to investment grade for the first time by Standard & Poor's, citing the improved financial profile from the mobile business.

Softbank was raised one level to BBB- from BB+, with the rating having a positive outlook, S&P said in a statement Monday.

It is the first time Softbank's long-term debt has been rated above junk by the ratings company, according to Ma­ki­ko Yo­shi­mu­ra, a Tokyo-based credit analyst at S&P.

The company, which is refinancing ¥550 billion in debt, has reported eight consecutive quarters of profit growth as it benefits from demand for the iPhone and iPad.

Net income will climb 35 percent to a record ¥256 billion in the year ending March 31, according to the average of 22 analyst estimates compiled by Bloomberg.