Last week was a notable one for bond issuance, with another Korean bank making its Australian debut; NAB providing price discovery for senior unsecured bond issuance by the major banks; Westpac making its euromarket covered-bond debut; and SPI (Australia) launching its second domestic bond issue.Korea Finance Corporation, which has an A rating, sold A$250 million of four-year floating rate notes priced at 305 basis points over bank bills. Presumably the basis swap works for them.NAB, which has an AA- rating, provided the highlight of the week with its A$1.5 billion, two-tranche bond issue. The bank sold A$750 million of fixed rate bonds priced at 185 basis points over swap to yield 6.26 per cent per annum. It also sold A$750 million of floating rate notes, priced at 185 basis points over bank bills.NAB copped some flack in the financial press for issuing the most expensive bonds yet by a major bank in the domestic market. However, the issue should, in fact, be viewed positively.NAB proved that there is significant demand for unsecured debt and not just covered bonds and, thus, has set a precedent and benchmark for further unsecured issuance to follow. Moreover, the bank highlighted the extent to which credit spreads have already contracted from the wide levels seen in January.The pricing of the unsecured bonds at 185 points over bank bills gives a pricing ratio of less than 75 per cent compared with the secondary market levels for the covered bonds issued by Westpac and CBA last month. While this is wide of the previously expected 50 to 67 per cent pricing ratios, it suggests that if CBA had issued unsecured bonds in January they would have been priced at 240 basis points over.NAB has done well at 185 bps over.SPI (Australia) Assets launched a minimum of A$200 million five-year bonds issued at a spread of 185 basis points over swap. Issuance by lower rated corporates at spreads in line with those achieved by the major banks or better is becoming a clear trend.Westpac, which has an AA- rating, sold €1.75 billion of four-year covered bonds after receiving orders for €3.5 billion. The bonds were priced at 72 basis points over mid-swaps. There was speculation that these would swap back by as much as 205 basis points over bank bills, but NAB Research was reported by KangaNews as putting the figure at 173 points, which sounds about right. Westpac's public covered bond debut in Europe was preceded by news of a private placement of Norwegian krone-denominated covered bonds. Westpac has sold or will sell NOK2.8 billion of ten-year covered bonds.And ANZ, which is rated AA-, raised A$98.5 million for four years in the Uridashi market. The bonds will yield 4.34 per cent per annum.