By Patrick Graham
LONDON (Reuters) - Gains for stock markets and a warning of possible intervention from Japan's finance minister knocked back the yen on Friday after a week of startling gains.
The yen surged at one point by as much as 2 percent against the dollar on Thursday, and Minister Taro Aso responded early on Friday by warning rapid currency moves were "undesirable," that the yen's were "one-sided" and that Japan would take steps as needed.
That is language that Tokyo has used in the past to flag intervention, and the yen's run to 17-month highs against the dollar has required investors to believe it would hold fire at least until after next week's G20 meetings in Washington.
"Of course there is some fear in the market," said Manuel Oliveri, a strategist at Credit Agricole (PA:CAGR) in London.
"But one has to bear in mind that there is the G20 agreement not to, and that to work any intervention would need to be large and really that means it would need the support of the Fed and the European Central Bank."
By 0738 GMT, the yen had lost 0.5 percent at 108.75 yen per dollar, still up more than 2 percent on the week and around 10 percent on the year so far.
The improved tone on European stock markets - still on course for their fourth straight week of losses - helped the Australian and Canadian dollars rise half a percent each.
But overall their U.S. counterpart was marginally higher against the basket of currencies that measures its broad strength (DXY), taking some comfort from Federal Reserve Chair Janet Yellen's promise on Thursday that the U.S. central bank was on course to tighten rates gradually.
Yellen's statement last week that the Fed should proceed cautiously in light of looming global risks to the U.S. economy have been at the heart of sharp falls over the past 10 days for the dollar against the euro and yen.
Both of those currencies have been treated as safe havens by investors sharing growing concerns that much of the developed world is falling into a debilitating cycle of deflation that central banks are powerless to stop.
"This is really just a bit of Friday respite," said a dealer with one international bank in London. "Where we go next week seems set to depend on risk appetite again. As long as stocks are falling, the dollar will be a sell on any rallies."
A Reuters poll of strategists released on Thursday showed the broader dollar rally that began in mid-2014 has nearly run its course and will only gain slightly over the coming year, with respondents saying risks to their forecasts are tilted more to the downside.
The dollar inched up 0.15 percent to $1.1360 per euro in morning trade in Europe.
"We think a combination of falling US real rates and elevated market volatility are weighing on the dollar against the current account surplus-backed euro and yen," analysts from BNP Paribas (PA:BNPP) said in a note.
"(But) we remain constructive on the dollar against the Australian and Canadian dollars."