German prosecutors are ramping up their years-long probe against Macquarie Group Ltd. staff over the Cum-Ex tax scandal — preparing to bring their first criminal charges, Bloomberg reports.

A Cologne prosecutor spokesman confirmed the pending indictments. Macquarie declined to comment.

Cologne prosecutors will initially bring charges against bankers who worked at Macquarie before 2012, people familiar with the matter said. As many as 100 people have been implicated, the lender said.

In total, Germany is probing 1,800 Cum-Ex suspects throughout the global financial industry. To date, more than 20 people have been convicted in German courts of the controversial practice.

One high-profile individual who has been found guilty is British hedge fund trader Sanjay Shah, sentenced by Danish judges in December to 12 years in prison for carrying out the same scheme in Denmark.

The Cum-Ex trading strategy obtained duplicate dividend tax refunds, until Germany put an end to the practice in 2012.

Macquarie has already reached two settlements over dividend trades between 2006 and 2009, paying $105 million to German authorities.

German law prevents prosecutors from charging companies with crimes but can add them as parties to criminal cases.

Tim Engel, the new head of Germany’s Cum-Ex prosecution, told reporters this week his office is taking a broad approach to prosecution, involving wading through copious pages of seized documents.