Australia's four largest banks are the political and fiscal bullseye for a savvy tax of IMF design. Labelled a levy, the tax is projected to cost the industry $6.2 billion over four years. This is a shade less than five per cent of the combined cash profits of ANZ, CBA, NAB and Westpac over the year to March 2017.It's one meaty core of an Australian government budget that is, for once, flooded with banking specific measures, many drawn from the work of recent public sector inquiries.The tax will be an annualised rate of 0.06 per cent applied to a spectrum of wholesale liabilities not covered by the Financial Claims Scheme.A threshold of liabilities of at least $100 billion confines the tax to the four largest banks. This minimum will be indexed, and banks of the scale of Bendigo and Adelaide Bank or Suncorp would need to merge to be drawn into this tax net.To patrol the inevitable and redundant flap over who bears the cost the Australian Competition and Consumer Commission will undertake a residential mortgage pricing inquiry slated, for now, to last until June 2018. As part of this inquiry, the ACCC will be able to require relevant ADIs to explain changes or proposed changes to residential mortgage pricing, including changes to fees, charges, or interest rates by those ADIs.A public sector authority - more a 'one stop banking cop shop' than a tribunal, will be set up "to create a new dispute resolution framework for the financial services sector." It will be known as the Australian Financial Complaints Authority, and cater for external dispute resolution "and greater transparency of internal dispute resolution by financial firms."In a direct prop for a favoured sector of the debt capital market, the Australian government will support a 'bond aggregator' model, covering set-up costs. There is, as yet, no actual 'model' for the National Housing Finance and Investment Corporation. Its framework may echo a UK scheme.The surge of measures in the first budget of the government since Malcolm Turnbull's coalition government edged out a bank-bashing Labor Party last year, the document draws together and finalises many works in progress.For once, it looks like the lobbying of the Customer Owned Banking Association and other activists succeeded in engaging financial regulators and the cabinet. The forthcoming Productivity Commission inquiry, confirmed last night - if still will no terms of reference on its website - has a marked leaning toward competition issues central to the agenda of mutual banks and credit unions.Also prioritised in the budget are new rules for credit cards, including forcing credit card providers to offer online cancellation and credit decrease options.The consumer group CHOICE reached for credit on this one."CHOICE has consistently pointed out that while big banks can approve a credit card online in 60 seconds, they do everything they can to stop consumers closing accounts. Banks will now have to make it as easy to drop debt as it is to arrange it," CEO Alan Kirkland said.There's still more:•    The