The Central Bank has re-assumed responsibility for a range of regulatory functions which had been carried out on its behalf by the Irish Stock Exchange since 2007.
The transfer was necessary under new EU transparency regulations.
These state that central banks are required to end arrangements they may have in place under which functions - such as policing stock market abuse - may have been delegated to other bodies by January 2013.
Deirdre Somers, chief executive of the ISE said it was "pleased to have been able to provide expertise and support to the Central Bank in relation to the prospectus, market abuse and transparency regulations for the past number of years".
"We are delighted following the unwinding of the delegation arrangement that these important regulatory functions now fully reside with the Central Bank," she said.
