This should be good news for the weaklings: their exporters will get more competitive, while pricier imports will ward off deflation. But it could also bring risks. Currencies have a tendency to overshoot. Firms and governments that have borrowed in dollars in recent years will have to pay more. Dollar borrowing by emerging-market firms has risen dramatically since 2008, to an estimated 70% of total bond issuance. And the temporary boost from a cheaper currency could provide the likes of France, Italy and Brazil (and increasingly Germany) yet another excuse to put off structural reform.