TORONTO -- The Canada Pension Plan Investment Board said Thursday that it's buying a 50-per-cent stake in a portfolio of office properties in Toronto and Calgary owned by OMERS for $1.18 billion.

The portfolio of seven buildings covers 4.2-million square feet of downtown office space, including the Richmond-Adelaide Centre in Toronto and the Centennial Place and Eau Claire Tower in Calgary.

OMERS, the pension fund of local government employees in Ontario, owns the properties through its real-estate arm Oxford Properties Group, which will continue to manage them.

This is not the first partnership between the investment wing of the Canadian Pension Plan and OMERS, with the two already jointly owning close to eight-million square feet of office properties.

OMERS said it would use proceeds from the deal to reinvest in new opportunities across its real-estate portfolio.