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Input: BRUSSELS/FRANKFURT (Reuters) - The European Central Bank will only stop pumping cash into the euro zone economy when it is confident that inflation is heading toward its target even without its extra help   the ECBâs chief economist Peter Praet  said on Monday.
Praet  one of the architects and sponsors of the ECBâs 2.55 trillion-euro ($3.17 trillion) bond-buying program  was responding to growing calls by some rate-setters to stop the scheme  which has been blamed for fuelling bubbles in the property and bond markets.
 Praet  said that before making any such decision the ECB needed to be confident that inflation was trending toward its inflation target of almost 2 percent and that it could withstand a withdrawal of stimulus.
âOnce the Governing Council judges that the three criteria for sustained adjustment have been met  net asset purchases will expire  in line with our guidance â  Praet  told an event in Brussels.
 He  also added the ECB had not decided yet how to end the asset purchase program  whether gradually or at once.
Asset purchases âcan expire at once or they can expire in a more gradual way. I think this is still one of the things the Governing Council has to discuss â  he  said.
âEven if incoming data were to validate the expectation of a gradual build-up of inflationary pressures  this would not be sufficient to affirm a sustained adjustment  if even less supportive monetary policy conditions were to imperil the inflation trajectory  Praet said.

ECB will only stop pumping out cash when confident about inflation