LONDON (AFX) - The euro drifted lower in midday trade as investors awaited US Federal Reserve chairman Alan Greenspan's speech, dealers said. "There isn't any particular reason why the euro's coming off its earlier highs," Halifax economist Nick Mirtchev said. "It's simply backing up a little after gaining on the weakness of US stocks. Nothing much has come out of the franco-German summit, and everyone's waiting to hear what Greenspan has to say," he said. Dealers said volumes are so light that the market could turn volatile this afternoon ahead of a long weekend in the US.