* Heavy positions seen acting against further euro gains
* Gains muted ahead of Yellen and Draghi speeches
* Graphic: World FX rates in 2017 http://tmsnrt.rs/2egbfVh
LONDON, Aug 23 (Reuters) - The euro held near the day's highs on Wednesday, propped up by strong readings on German and French PMI surveys though analysts warned the single currency's gains could be short-lived due to concerns about heavy one-sided bets.
"In terms of the euro positioning, we are at extremely stretched levels both against the dollar and the pound," said Richard Falkenhall, senior FX strategist at SEB, adding there was little likelihood of Draghi signalling any policy change at Jackson Hole.
The euro hopped 0.23 percent higher to the day's highs at $1.1788 against the dollar and climbed to a fresh 10-1/2-month peak against the British pound, near 92 pence.
Investors are awaiting speeches from Fed Chair Janet Yellen and Draghi at Jackson Hole on Friday, though neither is expected to announce new policy messages. In a speech in Germany on Wednesday, Draghi steered clear of market-sensitive comments.
PMI data from Germany and France propped up the single currency, with both countries registering strong private sector growth in August, separate surveys showed. That served to lift confidence that the euro zone's biggest economies are likely to maintain their robust momentum in the September quarter.
Latest positions according to CFTC data indicate that long euro bets are at their biggest levels in nearly seven years and the euro's strength has lured some of the world's biggest bond investors back into euro zone debt.
The dollar struggled against its rivals with a broad trade-weighted index falling to 0.2 percent on the day to 93.35, with very little in terms of top tier economic data to change the dollar outlook until Yellen's speech.
Political noise also weighed on the greenback's outlook though some market strategists said the dollar may be ripe for a bounce.
At a rally with his supporters in Phoenix, U.S. President Donald Trump reaffirmed his vow to build a wall on the U.S.-Mexican border. "If we have to close down the government, we are building that wall," he said.
"This years heavy unwind in long dollar positions suggests that currently the dollar should be more susceptible to good news than to bad," Rabobank strategists said in a note.
For Reuters Live Markets blog on European and UK stock markets see reuters://realtime/verb=Open/url=http://emea1.apps.cp.extranet.thomsonreuters.bi z / c m s / ? p a g e I d = l i v e m a r k e t s (Reporting by Saikat Chatterjee; editing by Mark Heinrich)