FX volatility hits five-year low; carry trade profitability has declined.

Euro trades at four-month high against the dollar on ECB's aggressive tactics.

Euro trades at four-month high against the dollar on ECB's aggressive tactics.

Central banks crowd out private investors; demand points to dollar strength.

Central banks crowd out private investors; demand points to dollar strength.

Currency weakens on pessimism about the outcome of todays EU summit.

Currency weakens on pessimism about the outcome of todays EU summit.

Weakness in U.S. economy suggests further Fed bond purchases.