Macquarie Airports has sold its 35.5% (A$120m) interest in Bristol Airport to Ontario Teachers' Pension Plan for £128m.
The sale price is 12.7% less than what Macquarie valued its share holdings at on 30 June 2009.
The sale will, however, allow Macquarie to acquire a 3.9% interest in Copenhagen Airports from the Ontario Teachers' Pension Plan, raising its interest in Copenhagen Airports to 30.8%.
Copenhagen recently signed a long-term aeronautical charging agreement with airlines which made its shares more attractive to Macquarie.
The transactions are expected to complete before the end of 2009.