Perceptions of improving credit quality had been shown in the performance of Asia-Pacific corporate and sovereign bonds in the last five weeks.

The cost of protecting Asia-Pacific corporate and sovereign bonds from default fell to the lowest in at least five weeks, according to traders of credit-default swaps.

The Markit iTraxx Australia index dropped 3 basis points to 117 basis points as of 9:23 a.m. in Sydney, a five-week low, according to Nomura Holdings Inc. and CMA.

The Markit iTraxx Asia index of 50 investment-grade borrowers outside Japan declined 1 basis point to 118 basis points as of 9:02 a.m. in Singapore, the lowest since May 13, Credit Agricole CIB and CMA prices show.

The Markit iTraxx Japan index fell 4 basis points to 118 as of 10:08 a.m. in Tokyo, the lowest since May 14, Morgan Stanley and CMA prices show.

Credit-default swap indices are benchmarks for protecting corporate and sovereign bonds against default.