It's a hot late summer in the Cum-ex saga. Just a few days ago, the trial against the former renowned Freshfields partner and tax expert Ulf Johannemann began in Frankfurt. Starting next Monday, the most well-known former top banker involved in Germany's largest tax scandal will be in court. Under case number 63 KLs 1/22, the trial against the longtime Warburg CEO and co-owner, Christian Olearius, will open at the Bonn Regional Court. He faces charges of severe tax evasion in 14 cases, with the prosecution estimating the damage to the treasury at nearly €280 million. The case revolves around Warburg Bank's Cum-ex trades, which had previously led to two British stock traders and several former Warburg managers below the executive level being tried and convicted. Warburg conducted stock circle trades involving prohibited collusions around the dividend payment date, both in proprietary trading and through investment funds that attracted wealthy private investors.

Olearius has denied all allegations thus far. The now 81-year-old had over several decades a significant impact on the traditional Hamburg private bank, M.M. Warburg. From 1986 to 2014 he served as the spokesperson for the shareholders and was the chairman of the supervisory board until the end of 2019 when he, along with co-owner Max Warburg, resigned from the oversight mandate allegedly under pressure from the financial regulator.

For the trial in Bonn, the court has scheduled 28 trial days extending into March 2024. Olearius will face the 13th Criminal Chamber, presided over by Marion Slota-Haaf. The former banker has assembled a defense team consisting of Peter Gauweiler (Gauweiler & Sauter law firm), tax and corporate law expert Klaus Landry (GvW Graf von Westphalen law firm), and Rudolf Hübner (Quinn Emanuel Urquhart & Sullivan law firm).

Even before the actual start of the trial, the case has caused significant controversy: Olearius failed last year with a complaint against the indictment before the Higher Regional Court in Cologne. In February of this year, the Bonn Regional Court itself caused a delay. In an unusual and less than flattering development for the court, the 13th Criminal Chamber had to declare its own chairman as biased after unofficial judicial transcripts from a parallel Cum-ex proceeding were found in the case files. Slota-Haaf (born in 1973) subsequently assumed the chairmanship.

Lastly, the trial against Olearius has a politically sensitive dimension. Questions still linger about the connections between the Warburg banker and the former First Mayor of Hamburg and current Federal Chancellor Olaf Scholz. Whether and what Olearius – possibly under oath – will say about potential attempted political influence during their meetings in 2016 is one of the intriguing questions in the upcoming Cum-ex trial.