The high street tailor said that Brigadier Acquisition Company, controlled by rival Crew Clothing’s owner Michael Shina, has contacted the takeover regulator to revoke the offer.
Moss Bross said “it will take all necessary action” to go ahead with the acquisition, agreed in mid-March.
The firm closed all its stores in March as coronavirus lockdown measures were implemented in the UK, commenting that it could weather significant revenue decline through 2020.
“It would be disgraceful if the takeover panel allows Brigadier to walk away,” said Nick Burchett, fund manager at Cavendish Asset Management, which has 6% stake in Moss Bross.
“If the Moss Bros acquisition falls through it could start a worrying trend for future deals.”
Moss Bros shares dropped 25% to 15.46p on Wednesday morning.