Commonwealth Bank's ASB has joined Westpac NZ in returning to the bond markets to issue floating rate notes.ASB has announced a five year issue of dual-tranche senior unsecured fixed and floating rate notes with an indicative margin of 110 to 115 basis points over three month swaps rates.Earlier this week Westpac NZ successfully reopened the market for bond issues by New Zealand's biggest banks after a four-month hiatus. The three year issue of NZ$385 million of floating rate notes at 75 basis points over swaps was the lowest spread since the Global Financial Crisis.The ASB issue, which is self managed, will be priced on July 16. ASB did not indicate the size of the issue.