SYDNEY, Feb 23 (Reuters) - Australia sold a record A$11 billion ($8.45 billion) of debt this week thanks to insatiable demand from local banks, calming market worries about the impact that losing its coveted triple-A rating could have on Australia's debt.
The new November 2028 bond issue received a whopping A$21 billion in bids at the clearing margin of 14 basis points over 10-year bond futures.
That allowed the government to pay a spread at the lower end of the 13.5 basis points to 16.5-basis points marketing range.
"We thought of a standard A$5 billion to A$7 billion, maybe A$8 billion issue size," said Ian Clunies-Ross, head of investor relations at the Australian Office of Financial Management (AOFM), the government's funding agency.
"So we were very pleasantly surprised with the level of demand."
While Australia's bond offers are regularly oversubscribed, the scale of demand for the latest issue suggests investors are unfazed by the prospect of a sovereign ratings downgrade.
Last year, S&P Global Ratings warned that Australia could lose its coveted triple-A credit rating if the government couldn't put its fiscal house in order by May, when the annual budget is presented.
The vast majority, or 85 percent, of the issue was sold domestically, AOFM data showed, with some investors surprised by the light participation of investors outside Australia.
"Offshore allocation dropped to 15 percent, the lowest ever for an AOFM syndication," Westpac said in a note.
International investors took 30 percent of a sale of 2021 bonds last month, and 65 percent of a 30-year issue completed in October.
"Offshore investors participate much more keenly when we extend our yield curve like a 15-, 20- or 30-year bond," said the AOFM's Clunies-Ross.
Among the domestic buyers, 35 percent of the issue went to banks' balance sheets, 25 percent to banks' trading books, 29 percent to fund managers, 5 percent to hedge funds and another 5 percent to central banks.
Local banks are large holders of Australia' sovereign bonds because there is a shortage of liquid securities that they must hold to help weather any potential funding crises.
Also whetting demand for the issue was an attractive spread over existing debt.
"It was fairly priced with a premium of one to one-and-a-half basis points," said Scott Rissman, director, liability-driven and overlay solutions at QIC, one of Australia's largest fund managers with A$32 billion in cash and fixed income.
The AOFM's Clunies-Ross said real money investors received their entire allocation, in contrast to hedge funds and banks' trading books which were aggressively scaled back.
The bonds, rated triple A by the three major ratings agencies, will pay a coupon of 2.75 percent and mature on November 21 2028.
ANZ, Commonwealth Bank of Australia, Deutsche Bank and Westpac Institutional Bank jointly led the issue which will settle on March 2. ($1 = 1.3011 Australian dollars) (Reporting by Cecile Lefort; Editing by Eric Meijer)