(Corrects headline, first paragraph and throughout story to clarify that only ATP is buying a stake in CPH and that Ontario Teachers Pension Plan already owned a 30 pct stake)
COPENHAGEN, Sept 14 (Reuters) - Danish pension fund ATP has agreed to buy a 27.7 percent stake in Copenhagen Airports (CPH) KBHL.CO from Australia's Macquarie MAP.AX for about 9.8 billion Danish crowns ($1.57 billion).
The transaction depends on approval by the Danish and European Union authorities and is expected to be completed in the fourth quarter, the parties said in a joint statement.
ATP estimated the offer price would be about 5,700 crowns per share, but said this could fluctuate depending on the date of completion.
Shares in the airport company rose as much as 12.3 percent after the announcement to 5,750 crowns per share. It closed at 5,620 crowns on Thursday.
Macquarie has invested more than 10 billion crowns during its 12 years of ownership in the company which owns Kastrup airport, the main international airport serving Copenhagen.
The Danish state owns 39.2 percent of the firm and Denmark's Finance Minister Kristian Jensen said on Twitter he was "very satisfied" that the future ownership was clarified and was looking forward to working with the new shareholders.
Canadian pension fund Ontario Teachers' Pension Plan (OTTP) holds a 30 percent stake in the airport company.
($1 = 6.2576 Danish crowns)