Mark Blinch / Reuters A real estate sign in front a house in Vaughan, near Toronto, May 24, 2017.

TORONTO — Criminals may be taking advantage of lax disclosure rules in the Greater Toronto Area to park billions of dollars in ill-gotten gains in the regional housing market according to a new report. The report out Thursday by Transparency International Canada, along with Canadians for Tax Fairness and Publish What You Pay Canada, found that some $28.4 billion worth of residential purchases since 2008 were done through corporate entities. The corporate structures, whether companies, trusts or nominees, allow the beneficial owner to stay hidden from law enforcement, tax authorities, and anti-money-laundering obligations. Watch: Real estate firms suck at halting money laundering, watchdog says. Story continues below.

Opaque ownership rules have made it a tempting target for global criminals, the report notes. "Canadian real estate has attracted the attention and money of corrupt government officials and organized crime syndicates from across the globe.'' The report further notes that $9.8 billion worth of the housing purchases were done without a mortgage, eliminating another layer of checks on sources of funds and beneficial owners. Over the same period, some $25 billion in mortgages were provided by unregulated lenders, which don't have anti-money-laundering reporting requirements. More from HuffPost Canada: No One Knows Who Really Owns Half Of Vancouver's Priciest Homes

'Corrupt Elite' Laundering Money In Canadian Real Estate: Report

StatCan 'Got It Wrong' On Foreign Homebuyers, Anti-Corruption Group Says The groups determined the numbers in the report by analyzing more than 1.4 million residential property transactions. They say the analysis focused on corporate entities because there is no data on nominee owners and trusts. The report notes that the potential hidden criminal activity could be making affordability issues worse. "By allowing criminals to invest in Canadian real estate, we are exacerbating crises in cities where housing is unaffordable and in short supply.'' The groups call for governments to require beneficial owners to identify themselves and make the information publicly available, along with other measures to make it easier to determine who truly owns property. They released a report in 2016 highlighting similar issues with Vancouver's housing market. The B.C. government has since proposed a registry of beneficial owners for property.