FSCO has release the industry data. Although it is bit outdated but it is still packed with very insightful information about the industry.
According to FSCO In 2014,
Mortgage brokerages reported that they arranged $148 billion of mortgage business and mortgage administrators reported that they administered $101 billion in mortgages.
On syndicated mortgages:
FSCO considers syndicated mortgages to be a high-risk investment that may not be suitable for all investors. Mortgage brokerages that are engaged in this activity are encouraged to review FSCO Bulletin No. M-01/15: Requirements for Promoting Syndicated Mortgage Investments to ensure they are able to demonstrate they have met their suitability and disclosure obligations to investors.