Searches conducted by the Competition Bureau at the head offices of Postmedia and Torstar as a result of that swap of 41 newspapers between the two, then 36 were shut down, including the Orillia Packet and Times, the Barrie Examiner and the Collingwood Enterprise Bulletin.
Nearly 300 jobs were lost.
Postmedia issued a statement saying it remains strongly of the view there has been no contravention of the Competition Act.
A Torstar spokesman says the company would also cooperate "completely."
The Commissioner of Competition said there is no conclusion of wrongdoing and no charges have been laid.
The commissioner has one year from a transaction to launch a challenge with the Competition Tribunal.