Of the "anniversary of the crash" features that have been common in recent days, the most revealing may be the Australian Prudential Regulation Authority's consultation document on liquidity management published on Friday.This document, in seeking to explain the rationale for a tighter definition of liquid assets and much harsher stress tests on banks, highlights a number of weaknesses in bank management in Australia following the collapse of Lehman Brothers in the US in September 2008; some of them not previously well known.One relates to the activities of some (obviously unnamed) foreign banks that operated with thin levels of liquid assets immediately after the crisis, and no doubt in order to aid the liquidity position of their bank at group level.Or to use the measured APRA language: "APRA observed isolated instances where foreign branches did not maintain their local liquid asset buffer at a reasonable level, given the stress they were experiencing."This led to some specific supervisory intervention, followed by a general tightening of APRA's approach to all branches."The document highlights the dilemma banks face in entering into the routine arrangements to buy back their own debt securities when investors seek to sell them.APRA noted that "under stress, buyback requests will increase significantly and it will be impossible for the ADI to refuse, since to do so would confirm the fears of the counterparties."Whether this was a lesson from the stress in offshore banking markets or based on a local incident APRA does not make clear.One better known weak spot is the reliance on what are still dubbed internet or online accounts, the domain of one bank hammered into submission by the crisis (Bank of Western Australia, sold late last year to CBA) and also of one other relieved by the introduction of the government guarantee (ING Direct).For the purpose of bank planning and stress testing APRA plans to assume that deposits in internet accounts are much more flighty than those of branch-based accounts.Some banks also appear not to have been able to report on their liquidity position in a prompt fashion when APRA came asking last year.