LONDON, Jan 21 (Reuters) - The FTSEurofirst 300 index briefly turned positive and the euro fell on Wednesday, as traders cited press reports saying the ECB's board had proposed a quantitative easing (QE) programme that would see it buy roughly 50 billion euros ($58.16 billion) in bonds per month.
The duration of the reported bond-buying plan was not immediately clear, with the WSJ reporting the purchases would be for a minimum of a year and Bloomberg reporting that they would not start before March and would last until the end of 2016.
The European Central Bank declined to comment. The FTSEurofirst 300 index was back in negative territory at 1502 GMT, down 0.3 percent.
The euro dipped from $1.1640/50 towards $1.1612 after the media reports. Most of the losses were seen against the Swiss franc, with the euro tumbling over 2.5 percent to 0.9846 francs.
"(The 50 billion-euro figure) at a minimum, meets expectations," BTIG's Dan Greenhaus said.
"(But) If this means the ECB is considering, or would implement, an open-ended form of QE, well then that's a whole other ballgame." ($1 = 0.8598 euros) (Reporting by Atul Prakash, Blaise Robinson and Anirban Nag; Editing by Lionel Laurent)