The number of mergers notified to the Competition and Consumer Protection Commission (CCPC) fell by 16% last year to 68.
Publishing its Mergers and Acquisitions Report, the CCPC said it had published 70 determinations through the year.
A total of four of those required the parties to agree commitments in order to secure approval.
These included the establishment of an electronics payment system by AIB, Bank of Ireland and Permanent TSB and the acquisition of certain KBC Bank Ireland assets by Bank of Ireland.
Tesco's purchase of Joyce’s Supermarkets and BWG’s takeover of McCarrick Brothers Wholesale also required binding commitments.
Last year also saw the first occasion since 2008 when a proposed acquisition was prohibited.
This related to Uniphar’s proposal to buy pharmacy solutions business NaviCorp Ltd.
The commission also completed seven Phase 2 investigations through the year, including a number involving the Irish banks’ purchases of the assets of the departing Permanent TSB and Ulster Bank.
"Although the total number of notified mergers was lower than 2021, we saw increasingly complex mergers notified, as evidenced by the unprecedented number of mergers which were subject to Phase 2 merger investigations," said Brian McHugh, Member of the Competition and Consumer Protection Commission.
"These Phase 2 cases invariably require thorough and comprehensive investigations before a determination can be made."
The CCPC also published in full the decisions it made regarding the various banking asset purchases.
"In publishing its banking decisions, the CCPC took the opportunity to raise concerns in relation to the overall competitiveness of the banking sector in Ireland and has continued to engage with the Department of Finance and the Central Bank on these matters," said Mr McHugh.
"The CCPC also gave careful consideration within the merger review process on how to mitigate the impact on consumers and SMEs through remedies where appropriate."
The CCPC said the area of professional services attracted the largest number of notifications at nine.
On average it took 17.9 days for determinations to be issued for non-extended Phase 1 investigations, it added.
Under the law, mergers and acquisitions that reach certain financial thresholds must be notified to the CCPC.
