How does it work? A 440 billion-euro ($600 billion) fund will be able to buy government bonds and lend money to banks and governments before they are in a full-blown crisis, making Europe's response to market jitters more rapid and pre-emptive.

What happened? The German parliament voted in favor of expanding German participation to guarantee loans of up to 211 billion euros, compared with 123 billion euros so far. It's important because Germany is the largest contributor to the fund.