Condo buildings line both sides of Gardiner Expressway in downtown Toronto, Ontario, Canada on August 31, 2017. Picture taken on August 31, 2017. REUTERS/Hyungwon Kang

TORONTO (Reuters) - Toronto, where home prices have risen 50 percent over the past five years, faces the highest risk of a housing bubble among 20 global financial centers, according to a UBS report released on Thursday.

Canada’s biggest city tops the UBS Global Real Estate Bubble Index, with Stockholm, Munich, Vancouver, Sydney, London and Hong Kong all remaining in risk territory for a bubble, according to the study by the Swiss bank.

Property markets in Boston, Singapore, New York and Milan appear fairly valued, UBS said.

Average home prices in the Greater Toronto Area, which surged to a peak of C$920,791 ($741,198.6) in April, have since come off as government measures to cool the market took effect.

The average sale price was C$732,292 in August, down about 20 percent from April but up 3 percent from a year earlier, according to the Toronto Real Estate Board.

“Expectations tend to be prone to exaggerations in boom phases,” UBS researchers wrote in the report.

“In the past, rising interest rates almost always triggered a crash in housing markets. In addition, the dependence of prices on international flows of capital represents an incalculable risk. Plus, once demand fell, even the low growth in supply would no longer provide an anchor.”