I think 80% of the mortgages originating in Canada end up on the balance sheets of banks under OSFI supervision, the larger banks. What Dominion Lending Centres is describing is the origination of mortgages. There's a difference between who originates a mortgage and who ultimately funds a mortgage. It's the funder who ultimately holds the risk. Regardless of whether their mortgage is brokered or originated by a broker, for the most part the risk of those mortgages in Canada is held by the banks.
The challenge that Dominion Lending Centres is communicating to you is that the options available to brokers on where they can send their mortgages are reduced when some of the finance companies are less able to fund their mortgages through portfolio insurance. It's more common for finance companies to use mortgage brokers than it is for banks, so measures that affect mortgage finance companies by design affect mortgage brokers. That's what that brief that you have is telling you.