Six senior bankers, including the former chief executives of Citigroup and Deutsche Bank in Australia, have been charged with criminal offences following a two-year investigation of ANZ's controversial capital raising in 2015.In dramatic developments last night, the Australian Competition and Consumer Commission revealed that criminal charges had been laid against former Citi Australia supremo Stephen Roberts and ex-Deutsche Bank CEO Michael Ormaechea.ANZ's group treasurer Rick Moscati has also been charged along with senior Citi executives John McLean and Itay Tuchman and former Deutsche executive Michael Richardson.ACCC chairman Rod Sims flagged last week that legal action was likely to be brought against ANZ, Deutsche and Citigroup over alleged cartel conduct relating to a $2.5 billion placement of ANZ shares in August 2015.The massive equity raising closed undersubscribed leaving the underwriters - Deutsche and Citigroup  - holding more than $700 million of ANZ scrip.The regulator's investigation is believed to have focused on talks between the three banks that allegedly aimed to minimise the impact on ANZ's share price of selling the overhang on the market.The ACCC said last night that the charges involve alleged cartel arrangements relating to trading in ANZ shares held by Deutsche and Citigroup.ANZ and each of the executives facing charges are alleged to have been knowingly concerned in some or all of the alleged conduct."These serious charges are the result of an ACCC investigation that has been running for more than two years," Sims said last night."Charges have now been laid by the Commonwealth Director of Public Prosecutions and the matter will be determined by the court."Each of the banks has issued statements in the last week asserting their respective intentions to defend the conduct of their organisations and staff."We believe ANZ acted in accordance with the law in relation to the placement and on that basis the bank intends to defend both the company and our employee," said ANZ chief risk officer Kevin Corbally.In a statement issued last week, Citi Australia said it would vigorously defend the allegations."Citi steadfastly denies the allegations made against it, and certain employees, by the Commonwealth Director of Public Prosecutions in relation to Citi's role as joint underwriter of the $2.5 billion equity placement conducted by the Australia and New Zealand banking Group in August 2015," Citi said."Citi will vigorously defend these allegations on behalf of itself and its employees."The legal action shapes as a possible game-changer for practices in Australian financial markets.Citi noted last week that the allegations relate to an area of investment banking that has not been considered by an Australian court in the past.The court case possibly shapes as one of the most damaging in ANZ's recent history and might eventually rank alongside the Opes Prime scandal for reputational fallout.Australia's anti-cartel laws were toughened a decade ago in the wake of the price-rigging case brought against packaging company Visy.Individuals found guilty of cartel conduct face up to ten years in jail and fines of up to $420,000 per offence.Under company laws, individuals are directly exposed to the penalties