MONTREAL -- New research suggests a small number of large commercial property owners are the most successful on Airbnb and are eating up the local supply of housing in Canada's three largest cities.

A team of urban planners from McGill University looked at Airbnb trends in Montreal, Vancouver and Toronto and noted a 50 per cent increase in the number of short-term rental properties year over year.

Using figures from an analytics firm, lead author David Wachsmuth said his team found that 10 per cent of hosts account for nearly half of the $430 million yearly revenue in the three Canadian cities.

The study, which is entitled "Short-term Cities: Airbnb's Impact on Canadian Housing Markets," was published Tuesday.

Airbnb rejected the findings, saying in a statement they misrepresent the profile of home-sharing hosts. It added that 80 per cent of them share their homes three or four times a month.

The company said only a small fraction of homes in Toronto and Vancouver are rented often enough to outdo long-term rentals.

"The author of this study has a history of manipulating scraped data to misrepresent Airbnb hosts, the vast majority of whom are middle-class Canadian families sharing their homes to earn a bit of additional income to help pay the bills," said Airbnb spokeswoman Lindsey Scully.

Wachsmuth said he doesn't dispute the 80 per cent figure, but added it is misleading.

"We found two big things: the first is that there has been a very significant concentration of Airbnb activity -- both in terms of what bookings are occurring and who is making money -- among a very small set of hosts," he said in an interview.

"What we found is that just 10 per cent of hosts are accounting for a majority of the revenue (50 per cent) that's being earned on Airbnb across the three cities. And that concentration is increasing."

Those multi-listing hosts include some people with multiple rental properties and, in some cases, larger commercial property management firms.

The study suggests the number of entire homes available, full-time listings, and hosts with multiple listings are all on the rise.

"What ties them together in common is these are not families renting homes while they're out of town ... these are people using Airbnb and other short-term rental platforms as a platform for making money off housing and doing so in a way that's reducing the available supply of housing in those cities," he said.

Wachsmuth suggested a few remedies, including limiting hosts to one rental property and putting an end to full-time rental homes by capping the number of nights they are available per year.

Lastly, Wachsmuth said he would like to see Airbnb and similar platforms enforce these changes by rejigging their websites.

For its part, Airbnb said it has worked with the Canadian cities in question to share data and information about its users.