The US government ended its guarantee scheme for US banks last week, although a guarantee will still be available in exceptional circumstances and at penalty rates. Nevertheless, there is still much talk about what should be done with bank guarantees, globally.Charles McCreevey, the EU commissioner for financial regulation and services, said during the week that the removal of bank guarantees will need to be done in a coordinated way and will present challenges and risks for the banks and regulators alike.He raised the prospect of an uncoordinated removal of bank guarantees resulting in funds moving from one banking system to another, with weaker, guaranteed, banks being favoured over stronger but unguaranteed banks. From here in Australia, this seems an unlikely scenario but the removal of guarantee support for the US banks will provide a live test. Cameron Clyne, CEO of National Australia Bank, speaking after delivering the bank's full year results, said the Australian government's guarantee support for the Australian banks should be left in place. His argument was perhaps a fair one.He pointed out that it was up to the banks themselves to choose whether they availed themselves of the guarantee or not, and they are generally choosing not to do so at the moment. Indeed, there was no guaranteed issuance by the Australian banks in the domestic market in October and only US$1.1 billion of guaranteed issuance offshore, that we are aware of. But market conditions could quickly change again and the banks may need that guarantee support once more.This, of course, conveniently ignores the philosophical argument about taxpayer support for private sector institutions. On the other hand, though, it makes it very hard to argue against the imposition of greater capital and liquidity requirements and tighter regulation, as all the banks are doing at the moment, if taxpayer support is expected to be available as needed. Moreover, the RBA pointedly told the banks not to expect emergency liquidity to be provided in the future, on the same day that Cameron Clyne made his comments. The RBA expects the banks to abide by APRA's proposal for the banks to hold greater liquidity going forward, so that if international bond markets close temporarily again, the banks will have sufficient liquidity to fund their operations for a month, rather than for just a week as is presently the case. In this context, it is interesting to have a look at the international debt maturity profile of the banks, i.e. the volume of international bonds issued by the banks, maturing over the next five years - more than A$230 billion of it. It is also useful to compare this with the maturities the banks faced this year and last year.The chart below shows the maturities for each bank, starting with 2009 and going through to 2014. What is immediately apparent is that 2009 has seen the largest volume of maturities, at more than A$60 billion, and that volumes will not be so great in future years. When it also considered that