* FTSEurofirst 300 falls 0.5 pct after drop in Chicago PMI
* FTSEurofirst 300 still posts best quarter in nearly 10 yrs
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By Dominic Lau
LONDON, Sept 30 (Reuters) - European shares fell on Wednesday after U.S. regional business activity contracted in September, but the main FTSEurofirst 300 index still managed to post its best quarterly rise in nearly 10 years.
The FTSEurofirst 300 index of top European shares ended 0.5 percent lower at 997.56 points, dragged down by banks and oil producers.
The index was up 17.3 percent in July-September, its biggest quarterly rise since December 1999. It rose nearly 16 percent in the previous quarter but was still down 39 percent from a peak in mid-2007.
Banks, which have rallied 171 percent since March, were among the stand-out losers after the Institute for Supply Management-Chicago business barometer fell to 46.1 in September from 50 in August.
Economists had forecast the index at 52.0. A reading above 50 indicates expansion in the regional economy.
BNP Paribas, HSBC, BBVA, UBS, Deutsche Bank, Commerzbank and Societe Generale were down 1.2-3 percent.
"In the near term, there is some vulnerability because the market did get quite overbought in the last week or two," said Ronan Carr, European equity strategist at Morgan Stanley in London.
Although the FTSEurofirst 300 is near its 12-month highs, the 14-day momentum and the 14-day Relative Strength Index have been trending down over the past week, a sign that the market could be overbought technically.
"On a six-to-nine-month view, the rally can go a little bit further. We do expect the recovery in growth to continue to come through and at the same time, monetary and fiscal policy will stay very loose -- positive backdrops for equities," Carr said.
Data, however, showed recovery would be erratic, with U.S. private employers cutting a bigger-than-expected 254,000 jobs in September. The U.S. economy contracted at a slower pace than previously thought in the second quarter.
Oil producers in Europe were also weaker on concerns over the patchy economic recovery. BP, Royal Dutch Shell and Total lost 0.4-1.3 percent. Insurers lent some support, with Legal & General up 6.1 percent on continued speculation it could be a takeover target. Italian insurer Generali said it had no interest in Legal & General, denying media reports and market speculation that have named it as a potential buyers.
Peers Aviva, Standard Life, RSA Insurance and ING Groep put on 2.7-3.9 percent.
Across Europe, Britain's FTSE 100 lost 0.5 percent but still posted its best-ever quarterly rise. Germany's DAX dropped 0.7 percent and France's CAC 40 eased 0.5 percent.
Volumes on the FTSEurofirst 300 were about 120 percent of the 90-day daily average volume.
OUTLOOK
Leading global investors cut equity holdings to their lowest level since February and boosted bonds and cash in September, a Reuters poll showed, as they grew nervous about adding more risky assets after the broad rally.
A separate Reuters survey showed major world stock markets would likely stutter to the end of the year following the strong push in March.
British retailer Marks & Spencer lost 3.4 percent, with some analysts saying that better-than-expected sales and profit margins were factored into a recent rally in its shares, while a downgrade in its cost guidance was not.
Also on the downside, Bayer shed 3.1 percent after UBS downgraded the chemicals and drug conglomerate to "neutral" from "buy" on valuation grounds.
Belgian pharmaceutical group UCB fell 3.3 percent. The company increased a six-year convertible bond offer to 450 million euros ($656 million) from 350 million euros, and said it could raise as much as 500 million euros to refinance debt.
Hedge fund firm Man Group, however, soared 7.5 percent after it said slowing outflows helped lift assets to an estimated $43.8 billion at end-September, at the top end of forecasts.
Smiths Group rose 6 percent after the technology company, which makes products ranging from security scanners to medical equipment, beat forecast for underlying pretax profit. (Editing by Rupert Winchester)