During the mid-1990s, Union Bank of Switzerland came under fire from dissident shareholders critical of its conservative management and lower return on equity.[101] Martin Ebner, through his investment trust, BK Vision, became the largest shareholder in Union Bank of Switzerland and attempted to force a major restructuring of the bank's operations.[102] Looking to take advantage of the situation, Credit Suisse approached Union Bank of Switzerland about a merger that would have created the second largest bank in the world in 1996.[103] Union Bank of Switzerland's management and board unanimously rebuffed the proposed merger.[104] Ebner, who supported the idea of a merger, led a shareholder revolt that resulted in the replacement of Union Bank of Switzerland's chairman, Robert Studer with Mathis Cabiallavetta, one of the key architects of the merger with Swiss Bank Corporation.[72][105]