GAM Holding AG, the troubled Swiss asset manager, said that Chief Financial Officer Sally Orton is stepping down as the firm works towards its takeover by Liontrust Asset Management.

Orton has been in her role for less than a year and will be replaced by former CFO Richard McNamara, according to a statement from the company on Tuesday. Separately, the firm said the Liontrust offer is expected to start on June 28 and conclude on July 25. The offer results are expected to be published in August.

GAM agreed to sell itself to London-based Liontrust for the equivalent of 107 million Swiss francs ($118 million) last month in a deal that would create a $66 billion global asset manager and seek to draw a line under years of turmoil. The GAM board reiterated it continues to “strongly recommend” that shareholders accept the Liontrust offer, which is also supported by some of GAM’s senior portfolio managers.

An investor group including French telecoms billionaire Xavier Niel is contesting the deal, arguing it undervalues the company. It is seeking to oust the board as part of its opposition and install its own slate of directors.