The spike in Portuguese bond yields could signal trouble for Europe.

BBC: Davos 2012: The unfinished and the unmentionable

Economists viewed his speech as a signal that the ECB would resume its bond-buying program.

FORBES: Drugged By Draghi: Markets Rally After ECB Chief Promises To Save Euro

The remarks seemed to signal that the ECB would step into bond markets where prohibitively high borrowing costs threaten Spain and Italy.

FORBES: Drugged By Draghi: Markets Rally After ECB Chief Promises To Save Euro

Investors are looking for the European Central Bank President to make good on his promise to do whatever is needed to protect the euro, interpreted by most as a signal that the ECB will intervene in bond markets.

FORBES: Draghi Does Not Please The Markets