While the company's share price is rallying and the cost of insuring its bonds from non-payment is falling, the Bloomberg Default-Risk Model signals deterioration in the firm's creditworthiness this year. Hiroe Kotera, a spokeswoman for SoftBank in Tokyo, declined to comment. SoftBank's share price has climbed 14 per cent since the start of the year, and the cost to insure against a default on its bonds has almost halved to 132.5 basis points in the same period. Even so, the risk of non-payment in the coming 12 months has risen to 0.5 per cent from about 0.3 per cent at the start of the year, according to the Bloomberg default risk model, which tracks metrics including share price, debt and cash flow. Its borrowings stood at the equivalent of about US$120 billion as of June 30. Moody's has a Ba1 rating on SoftBank, its highest speculative grade, and a B3 rating on its US subsidiary Sprint Corp, five levels lower.