They effectively gain a larger market share or even a monopoly in those areas. The idea being that Postmedia shuts down the Torstar paper it just acquired. Postmedia will sell more of their own papers in that area because it no longer has to compete with the Torstar newspaper it just effectively put out of business. And visa versa.
We know the business case of shutting down. But why not just shut, why sell and shut?
Same thing with pro sports teams. Why should taxpayers foot the bill for stadiums etc? Taxpayers dont share in their profits.
Could it be that the one that is sold in each case, is the weaker in that two-paper town?
So Torstar owns the Smallville News.
Postmedia owns the Smallville Sun.
Torstar owns the Biggerville News.
Postmedia owns Biggerville Sun.
In each case above, the bold one is the stronger paper (larger circulation, more ad revenue).
So if Postmedia just closed the Smallville Sun, only on the condition that Torstar closes the Biggerville News, maybe that's some type of illegal collusion. But if they sell/swap, both Torstar and Postmedia get all the bad papers, so they close more or less automatically.