The deal is due to clear its final hurdle at a hearing to approve a fast-track takeover process known as a scheme of arrangement.
The group – known as Justice for Nisa – has hired lawyer to represent them at the hearing after raising funds from other unhappy shareholders, according to a report in The Guardian.
The group wrote to other members outlining their plans: “Since the vote was forced over the line by a minute majority, a group of members have been working hard to create a valid and worthwhile representation to the court hearing, objecting to the takeover on a number of grounds.
“There appears to be an ever increasing number of shareholders who regret the decision to sell and a swell of support to challenge the completion.”
One Nisa member confirmed to Talking Retail that he received the message from this “notorious group” and most members were fed up with the “nuisance” they were causing.
A Nisa spokesman said: “Nisa remains confident that all appropriate legal process has been observed throughout the scheme of arrangement and vote – which resulted in overwhelming member support for the Co-op’s acquisition.”
The Competition and Markets Authority cleared the Co-op’s purchase of Nisa last week following an investigation, concluding that the proposed merger does not create competition concerns.