Is foreign money the driving factor behind skyrocketing home prices in Toronto and Vancouver? Yes, if you ask BMO chief economist Douglas Porter. He issued a chart Friday in an effort to confirm the role of foreign money in rising property values.

(Chart: Bank of Montreal) The chart shows that, historically, house prices tracked growth in mortgage borrowing. (The big exception being during the 2008-09 financial crisis, when house prices fluctuated wildly.) But now house prices are spiking upwards, even as mortgage borrowing has slowed from a few years ago. "Something besides domestic borrowing has clearly fanned the flames. We will simply note the anecdotal evidence that many foreign buyers do not borrow to buy," the economist wrote.

Vancouver's False Creek. (Photo: Kim Rogerson via Getty Images) Porter's analysis came in response to an analyst who had said that blaming foreign money for the house price spike is "complete nonsense." The Financial Post attributed that quote to Paul Ashworth, an economist with Capital Economics. Last month, Ashworth issued a report that laid the blame for house price growth solely on borrowing. He, too, issued a chart to press his point.