Macquarie's chief executive and her predecessor are among 60 present and former staff to be named as suspects by German authorities, the Australian bank said, as Germany's biggest post-war fraud probe into sham trades unfolded.
Macquarie says prosecutors would likely want to interview Macquarie's former chief executive Nicholas Moore and Shemara Wikramanayake, the previous head of asset management who replaced Moore in December 2018.
German prosecutors and tax authorities are seeking to recover billions of euros from traders and banks that prosecutors say profited from such schemes.
The country estimates the schemes cost it more than 5 billion euros ($A8 billion) in total, although leading experts estimate that the damage may be twice as high.
Prosecutors allege that players in the so-called cum-ex scheme misled the state into thinking a stock had multiple owners who were each owed a dividend and a tax credit. Two bankers are now on trial, with many more expected to follow.
The investment conglomerate said in a statement it had been responding to requests for information about its activities but that no current staff had yet been interviewed by prosecutors.
"Macquarie continues to cooperate with German authorities in relation to an historical German lending transaction in 2011," the statement said.
Most of the 60 staff "are no longer at Macquarie and some of whom were already named in relation to the 2011 lending matter, including the MGL CEO," the bank added.
Macquarie acted as a lender to a group of funds involved in the share trading in 2011 and has previously said it was one of over 100 financial institutions involved in this market, from which it withdrew in 2012.
Prosecutors in Cologne made a major breakthrough in 2017 when a group of bankers, including a former Macquarie employee, offered information that showed Santander, Macquarie and others profited from the scheme.
On Thursday, Macquarie said the "amount at issue" was not considered material and that it had "provided for the matter".
Germany changed and clarified the law in 2007, 2009 and 2012 to prevent cum-ex trades, but the case has fuelled mistrust of banks among ordinary Germans.
The discovery of the trades in Germany and Denmark, where tax authorities say they lost $2 billion in rebates, prompted investigations by other countries including Austria and Belgium, which have found they were also affected, albeit on a far smaller scale. (Reporting by Paulina Duran in Sydney; Editing by John O'Donnell and Barbara Lewis)