The chief executive of Revolution Bars, Mark McQuater, has resigned and is leaving the business immediately.
The UK bar chain has received separate takeover offers from rivals Deltic Group and Slug and Lettuce-owner Stonegate Capital.
Revolution’s board has already rejected a merger proposal from Deltic Group.
On Tuesday, Revolution’s shareholders rejected Stonegate’s £101.5m bid which had been recommended by Revolution’s board.
Revolution, which owns 68 High Street bars, saw its share price fall sharply in May after it said that its profits had been hit by the Living Wage, new apprenticeship levy and above-inflation increases in business rates.
Revolution’s chairman Keith Edelman will assume the role of executive chairman until a suitable replacement for Mr McQuater has been found.
The Deltic Group owns 57 nightclubs in the UK, including the Pryzm, Bar & Beyond, Steinbeck & Shaw, Atik and Fiction brands.
The nightclub operator is keen to merge with Revolution to create a “powerhouse group” listed under the Revolution name.
Under the terms of the proposal, existing Revolution shareholders would own 65% of the new company, while Deltic would own the remaining 35%.
After meeting with Deltic representatives in August, Revolution said that a merger was “not in the best interests of shareholders at this time”.
The bar chain rebuffed Deltic’s merger proposal in early October, and Deltic has said it has no plans to make a cash offer for Revolution.