Irish firms were involved in mergers and acquisitions worth $104.6bn last year.
This represents a six-fold increase in the value of such deals compared to a year earlier, according to Refinitiv which compiled the data.
It said the annual total has only been exceeded once since its records began 22 years ago.
2021 saw a total of 690 deals involving Irish businesses.
That, according to Refinitiv, is a 58% rise on the number in 2020, and also the highest level since it began recording the information in 1980.
Among the biggest of these was aircraft-leasing group AerCap Holdings NV's deal to buy GE Capital Aviation Services for $31.2bn.
Icon Plc also paid $11.9 billion for US-based PRA Health Sciences Inc.
In total there were 230 outbound merger and acquisition deals, worth $67.7bn.
Permanent TSB's offer to buy departing Ulster Bank assets for $8.6 billion was among the largest M&A deals involving both an Irish seller and buyer.
The total value of such transactions in 2021 was $12.3bn.
While inbound mergers and acquisitions, where a foreign buyer targeted an Irish firm, reached $18.1bn.
