Two ambulance-chasing firms are inviting CBA shareholders to punch themselves in the head and pay the firms for the privilege.

A narrower version of the story is that lawyers Maurice Blackburn and litigation funder IMF Bentham are out to profiteer by provoking one group of innocent CBA shareholders to rip money off another group of innocent CBA shareholders and further damage the share price in the process.

It's a prime example of how the often-noble class action vehicle can be used primarily to benefit lawyers and litigation funders gaming the legal system.

The MB/IMF class action is not necessary to "teach the CBA a lesson" – the regulators' actions and market reaction are doing that. It won't punish the people most responsible for the CBA's money laundering failure – they are mainly gone or going. It's about generating fees and profits for MB and IMF.