Hundreds of institutional shareholders, including US and European investors, have registered their interest in the open class action brought by Maurice Blackburn against Commonwealth Bank over the Austrac scandal.Andrew Watson, Maurice Blackburn's national head of class actions, told Banking Day that major offshore institutions were expected to formalise their participation in the case."We're expecting broad-ranging participation both from Australian institutions and major overseas-based institutions, including those in the United States and the UK," Watson said.CBA's share register includes some of the world's leading activist institutions, such as the California Public Employees' Retirement System.Around 169 local and offshore institutional investors hold slightly more than half of the total ordinary shares of the bank.Watson's comments came after Maurice Blackburn lodged a statement of claim in the Federal Court over CBA's non-disclosure of anti-money laundering breaches before Austrac launched court action against the bank on 3 August.Watson said CBA shareholders were sending "a clear signal" that they would not tolerate corporate misconduct that has mired the bank in bad news in recent times.In a media release Maurice Blackburn stated CBA had "publicly confessed" that its board was aware of the breaches in the second half of 2015 but chose to say nothing to the ASX until the first week of August this year when Austrac launched Federal Court proceedings.Watson said when information about the alleged breaches was revealed to the market there was "a significant drop in the value of an otherwise stable stock"."Our investigations and analysis show that this drop was in the top one per cent of price movements that CBA experienced in the past five years, so clearly the news was of material significance to shareholders," he said."Investors would expect the CBA to take a leadership role in setting high standards of corporate conduct."Given the opposite appears to have happened here, shareholders have every right to seek accountability by exercising their legal rights in the most efficient and effective way possible - through the class actions regime."Maurice Blackburn asserts in the statement of claim that thirteen CBA directors knew of the alleged breaches for up to two years before they were disclosed. Senior executives alleged to be aware of the alleged breaches included the CEO Ian Narev and chief risk officers Alden Toevs and David Cohen.CBA told the ASX that it intends to "vigorously defend the claim".In a separate statement to the ASX, litigation funder IMF Bentham announced that it had removed all conditions on providing financial support for the case.It also announced that CBA shareholders who bought shares after 1 July 2015 would be eligible to participate in the case so long as they held some or all of their holdings until 3 August.Previously, only shareholders who purchased CBA scrip from 17 August 2015 had been invited to participate in the class action.Thousands of retail shareholders have indicated they will participate in the class action, including long-time stockmarket investor, William Phillips."I'm an accumulator of stock and I don't sell unless something is really on the nose, but I recently