In a trading update yesterday, the management of National Australia Bank alluded to, but didn't really address, the issues arising from the payment processing issues that afflicted the bank in late November and which remained unresolved until the end of January. Mark Joiner, finance director, told an investor briefing that there was "no material financial impact from the batch-processing issue, although the full implications of that are not yet known." Managing director Cameron Clyne told the briefing that "what we are trying to do is manage the business for positive 'jaws' [revenue growth greater than cost growth], so... we're not giving any further guidance on costs, but that's how we're trying to manage the business.   "In terms of the major systems investments, they're on track and proceeding. The incidents we had late last year had no impact on those programs. We've still got no impact in terms of our delivery schedule. "We've obviously got a series of major releases coming through the back end of 2011, and then more into 2012, so [with] the Next Generation [technology platform] we'll switch more and more functionality over, but that's all proceeding on time and on track."