Non-residents likely don't need financing (have cash, will travel), hence why the Federal stress test on mortgage qualification -- and shortened amortization on mortgages  -- only had limited affect (actually, it affected all true purchasers who wanted a home, but less so the non-resident). The real issue is how to stop speculators and flippers. Eliminate assignmet clauses and charge 100% cap gain on sales within 12 months of closing.