Over a quarter of the entire office stock in Dublin has traded since the beginning of 2013, according to a report from estate agents Savills.
That equates to over 1 million square metres of office space.
The proportion is even higher in Dublin's 'central business district' with 38% of office space changing hands in that time.
John McCartney, economist and director of research at Savills Ireland, said the rate of activity reflected a glut of supply as NAMA and lenders put the assets associated with non-performing loans up for sale.
It was also due to rapid growth in services employment which created strong occupier demand and low vacancy rates, he added.
Mr McCartney said he expected prime headline office rents to increase by 14% by the end of this year.
Savills noted that institutional investors and REITs have been the biggest buyers of office property since the start of 2015, accounting for 41% of modern office purchases by volume and 80% by value.
The average lot size for these players was just under €50m.
It also noted the steady increase of foreign office buyers. These accounted for just 29% of spending on Dublin offices during 2013, but this rose to 62% in 2015 and 68% in the first quarter of 2016.