Credit Suisse AG (CS) shares rose to the top of the market in Zurich Tuesday after Swiss-based activist investor RBR Capital Advisors confirmed it had taken a stake in the investment bank and is speaking to management about potential changes to its structure and strategy.

The confirmation followed a report from London's Financial Times newspaper that said the RBR was looking to press Credit Suisse towards a plan that would see it split into three groups focused on private wealth management, asset management and investment banking. 

"As with all our shareholdings, we are in direct contact with the Executive Board and the Board of Directors," RBR told TheStreet. "We have discussed various strategic alternatives for successful further development with the company. RBR will shortly be explaining its views to the capital market and the public in detail."

Credit Suisse shares were marked 1.33% higher in Zurich and changing hands at Sfr15.65 each by 2:00 pm local time after earlier rising to Sfr15.83, the highest since March 3, in the opening minutes of trading.

The move represents one of the most significant activist moves in the European market, and the second attempt to invoke change at a major Swiss company after Dan Loeb's Third Point Capital revealed its 1% stake in Nestle SA (NSRGY)  in late June.

The push for change is also the latest in a series of challenges for CEO Tidjane Thiam, who rejected pressure to spinoff the group's domestic operations earlier this year in favor of a $4 billion rights issue to bolster its balance sheet.

Thiam, who took the helm of the Swiss bank in 2015, called the capital raising, and the solid start to the year "an important step in the execution of our strategy" and said Credit Suisse was making "good progress in our strategy of being a wealth manager with strong investment banking capabilities thanks to the continued trust of our clients and the hard work of our teams."

Thanks in part to the group's capital increases, Credit Suisse shares have under-performed both the domestic Swiss market and the broader European banking sector so far this year, with shares rising only 7% against a 12.6% advance for the SMI benchmark and an 8.7% advance for the Stoxx Europe 600 banks index.

RBR is run by Rudolf Bohli, an ex-analyst and trader, and has launched three activist campaigns and two director-election battles at two companies in  recent years, according to FactSet, including an unsuccessful pitch to install three dissident directors at the board of GAM Holding AG.

Last year, RBR and another fund, Cologny Advisors LLP, sought to install two dissident directors at Gategroup Holding but were defeated at the company's annual. The fund had more success in 2015 when a director battle the fund had instigated also at Gategroup for four dissident seats was settled for two board seats.

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