The Shareholders Association is unhappy with Guinness Peat Group over the €138 million fine that its European threads business must pay.
Coats lost its case to have the fine dropped for its part in a price fixing cartel in zips and fasteners between 1977 and the late 1990s - before GPG took ownership of Coats.
Shareholders Association chairman John Hawkins says GPG previously indicated the fine had been adequately provided for.
Last week GPG said it had $45 million set aside though it did have adequate banking facilities to cover the fine.
Mr Hawkins says GPG has not been fully upfront, the company's response to its query has been less than satisfactory and the Association is considering taking the matter to regulators.
"When push comes to shove we discover that only about a third of the fine is provided for in the balance sheet. We have serious concerns as to whether that constitutes adequate."
Mr Hawkins says the matter will be discussed at a board meeting later this week.