GAM's Extraordinary General Meeting is turning into a showdown in the bidding war for the asset manager. Now there's a dispute about that too.

The investor alliance comprised of NewGAMe and Bruellan is requesting a change in the date for GAM's extraordinary general meeting, seeking to have it moved to the end of August from the scheduled date of August 18, the group announced Tuesday.

The postponement is intended to give shareholders time to vote with full knowledge of the outcome of the takeover bid by British fund firm Liontrust, the group said. Liontrust recently extended the bid deadline to August 23 as is seemingly struggles to secure 60 percent of the vote. NewGAMe & Co launched a counteroffer for a portion of GAM's outstanding shares.

Ultimatum Set

Nevertheless, the EGM would probably be in favor of the GAM management which supports the sale to Liontrust. Key shareholder representatives including ISS and Glass Lewis are behind the sale, according to reports. In a separate announcement on Tuesday, Liontrust said it received the green light from the UK financial regulator FCA for the GAM acquisition.

The company is playing for time. If GAM doesn't publicly announce the rescheduling of its annual general meeting by August 10, the investor group led by NewGAMe will withdraw the submitted proposals and request a new meeting once the results of Liontrust's bid are known.