Banks urge Ottawa to tighten mortgage rules

<br>The heads of the country's six largest banks have privately told policy makers that they fear the wide-ranging economic fallout of a U.S. style binge-and-collapse in housing. To head off any chance of that happening, they are willing to accept tighter rules on mortgages that would slow the real estate market, even though it would mean forgoing some short-term profits from giving out ever bigger mortgages as home prices jump.<br><br>