The Reserve Bank of Australia's September board minutes, released yesterday, show the RBA is now extremely confident about Australian banks' stability.They also emphasise the RBA's focus on the borrowings of Australian households - the sector that the RBA sees as the most likely source of instability in the near future.The minutes emphasised that non-performing loans to Australian households were "relatively low" and non-performing housing loans, in particular, were well below levels in the United States and parts of Europe. And it said households "appeared to be taking a more cautious approach to their finances", repeating a common RBA theme.Meanwhile the corporate sector was recording "gearing and interest payment ratios close to the lowest levels in three decades".The minutes also show the RBA focusing on the Big Four's rising profitability and declining bad and doubtful debts.And the RBA is more confident that bad debts in US, European and Japanese banks won't get much worse now: "In a number of cases, the flow of provisions for bad loans appeared to have peaked."