* FTSEurofirst 300 index falls 1.1 pct
* Man Group slumps on client exit
* Banks fall after Tuesday's surge
By Joanne Frearson
LONDON, Sept 28 (Reuters) - European shares fell on Wednesday after the biggest one-day jump since May 2010 on Tuesday, as concerns grew about obstacles in the way of plans to ease the debt crisis, while Man Group dived after clients pulled out of the hedge fund manager.
Man Group slumped 21 percent to become the heaviest faller in Europe after total assets under management fell to $65 billion at end-September from $71 billion at end-June due to the volatile market conditions.
Concerns about euro zone rescue plans rose as Germany suggested parts of the new Greek bailout might be reopened for negotiation depending on what the "troika" audit found, while the Financial Times reported a split had emerged in the euro zone over the deal.
Uncertainty over how countries will vote on widening the scope of the European Financial Stability Facility (EFSF) added to the worries, with Finland voting on Wednesday and Germany on Thursday as analysts expect some opposition.
Banks which surged in the previous session on hope the EFSF would be leveraged as well as talk the European Central Bank was keeping its options open for a rate cut featured among the worst performers.
"The market has obviously got enthusiastic about discussions about the EFSF," Andrea Williams, who manages $2.1 billion in assets for Royal London Asset Management, said.
"But we are a long way from it being concluded, there are still many countries to ratify it. We have been underweight on banks for the past three to four months and would not change this position."
The STOXX Europe 600 banks index was down 1.2 percent on the worries about how the debt crisis would be tackled after a 6.8 percent rise in the previous session. They are still down 32.4 percent for the year.
French bank BNP Paribas , which has exposure to sovereign debt in Greece and Italy, was a stand out loser on the French CAC on the uncertainty and fell 2.5 percent.
BNP Paribas has fallen 41.4 percent since late July on increasing worries the bank could be hit by a funding squeeze if the debt crisis worsens, as well as concerns about slowing growth.
By 0830 GMT, the pan-European FTSEurofirst 300 index of top shares was down 1.1 percent at 928.11 points after making their biggest one-day gain since May 2010 in the previous session on hopes of a coordinated plan to ease the debt crisis.
The index briefly pared losses early on after European Commission President Jose Manuel Barroso suggested Greek banks could receive more help and said once there was deeper economic integration within the bloc the region could issue jointly underwritten bonds.
But it quickly fell back, with many uncertainties about the euro zone debt crisis remaining.
Trading firms said they were only seeing clients position themselves for short-term moves.
"It is going to be a choppy session," Joshua Raymond, market strategist at City Index, said.
"Sensitivities remain high especially if there is going to be renegotiation of the bailout for Greece and we are seeing clients change positions on an hourly basis."
Thomson Reuters Datastream showed the ratio of put/call open interest on the Euro STOXX 50 eased to 1.1025, hitting a more than 10-month low, suggesting traders were wary about equities despite the recent sharp rebound.
Support for the FTSEurofirst 300 index was seen at 917 points its 50 percent Fibonacci Retracement from its March 2009 sell-off to its February 2011 high, with resistance at its 38.2 percent Fibonacci Retracement or 981.09. (Reporting by Joanne Frearson; Editing by Helen Massy-Beresford) ============================================================ For rolling updates on what is moving European shares please click on ============================================================ For pan-European market data and news, click on codes in brackets: European Equities speed guide................... FTSEurofirst 300 index.............................. STOXX Europe index.................................. Top 10 STOXX sectors........................... Top 10 EUROSTOXX sectors...................... Top 10 Eurofirst 300 sectors................... Top 25 European pct gainers....................... Top 25 European pct losers........................
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