National Australia Bank has launched a hybrid issue, aiming to raise A$750 million of capital with an offer of securities paying a margin of 2.95 to 3.15 per cent over the bank bill rate.NAB Capital Notes 4 are convertible, subordinated notes that will pay quarterly, non-cumulative distributions. Distributions are expected to be franked.The notes will qualify as additional tier 1 capital for the group.NAB may redeem the notes in September 2027.NAB's offer comes a week after Macquarie Bank raised $445 million of capital through an issue of hybrids, Macquarie Bank Capital Notes 2.The Macquarie notes are priced at a margin of 2.9 per cent and have a call date of June 2026.