Drinks company C&C has been fined 90,000 euro (£78,000) over its failure to comply with rules designed to prevent stock-market abuse.
The Ireland and UK-based manufacturer, marketer and distributor was penalised for failing to keep up-to-date insider lists of people who receive sensitive company information.
An investigation by the Central Bank of Ireland uncovered three breaches of market abuse regulations and rules.
Derville Rowland, head of enforcement at the regulator, said the insider lists are an essential record.
"The Central Bank regards the proper maintenance and updating of insider lists as essential given their key importance as a tool in the prevention and/or detection of market abuse through the illegal use of inside information," she said.
Under financial rules, companies must draw up and maintain insider lists with names of all employees, contracted staff, advisers and anyone else with access to inside information.
In a statement, C&C Group said it was an administrative failure. The company said: "C&C has confirmed to the CBI (Central Bank) that, since 2009, it has implemented a number of changes to its practice and procedures. The CBI (Central bank) has confirmed that the matter is now closed."
The Central Bank said the breaches occurred from January 2008 to January 2009. It said the penalty reflected the importance of properly maintaining and updating insider lists.
The Central Bank also confirmed the breaches have been rectified.
C&C's principal brands are the leading Irish cider brand, Bulmers, and the international cider brand, Magners. It also manufactures Tennent's beer and Gaymers cider.