By Joanne Frearson LONDON, Dec 19 (Reuters) - European shares ended lower after a volatile session on Friday, weighed down by commodity shares that tracked falls in crude and copper prices. The FTSEurofirst 300 index of top European shares was down 0.45 percent at 823.37 points, having traded between 810.2 and 830.92. Traders ascribed the volatility to quadruple witching -- or the expiry of options and future contracts -- at different points during the day. "It's got the 'Friday before Christmas' feeling. It's very quiet and volumes are thin," said Jim Wood-Smith, head of research at Williams de Broe. "No one wants to take big bets on the banks and basic resource stocks are down following lower crude and metal prices," he said. Energy stocks took the most points off the index. New York January crude futures CLc1, which expire on Friday traded down 4.7 percent at $34.44 a barrel, while February futures CLc2 were up 1.1 percent to $42.16 a barrel. BG Group (BG.L: Quote, Profile, Research, Stock Buzz), Royal Dutch Shell (RDSb.L: Quote, Profile, Research, Stock Buzz), BP (BP.L: Quote, Profile, Research, Stock Buzz), Total (TOTF.PA: Quote, Profile, Research, Stock Buzz) and ENI (ENI.MI: Quote, Profile, Research, Stock Buzz) slipped between 1.2 percent and 4.2 percent. Mining stocks fell as metal prices retreated. Earlier, copper MCU3 had fallen to a new four-year low of $2,860 a tonne, though by late afternoon it was trading higher at $2,934.75. BHP Billiton (BLT.L: Quote, Profile, Research, Stock Buzz), Rio Tinto (RIO.L: Quote, Profile, Research, Stock Buzz) and Vedanta Resources (VED.L: Quote, Profile, Research, Stock Buzz) fell by between 1.8 and 9.5 percent. "Mining stocks are still trading at relatively high multiples and I believe that we will see some hefty downwards revisions in that sector," said Darren Winder, head of strategy research at Cazenove. Anglo American (AAL.L: Quote, Profile, Research, Stock Buzz), Xstrata (XTA.L: Quote, Profile, Research, Stock Buzz) and Antofagasta (ANTO.L: Quote, Profile, Research, Stock Buzz) were down 7.1 percent to 11.3 percent after UBS downgraded the three miners to "neutral" from "buy". CENTRAL BANKS INJECT MORE CASH Central banks worldwide announced their latest effort to inject cash into the financial system, but said demand for U.S. dollars has declined, as sign the global credit crunch may be easing. [ID:nN19433399] Led by the Federal Reserve, the banks said they will continue to provide dollar liquidity in the first quarter of next year. Automobiles weighed despite the White House announcing it would make available loans from the Troubled Asset Relief Program to struggling automakers. [ID:nLJ125834] Peugeot (PEUP.PA: Quote, Profile, Research, Stock Buzz), Volkswagen (VOWG.DE: Quote, Profile, Research, Stock Buzz) and Renault (RENA.PA: Quote, Profile, Research, Stock Buzz) were down between 3.8 percent 7.8 percent. Banking stocks were in the doldrums. Standard & Poor announced downgrades and outlook changes to the ratings of 12 major U.S. and European financial institutions. Merrill Lynch said European banks face another "very tough" year in 2009, mainly due to deteriorating asset quality and the negative impacts of deleveraging. Standard Chartered (STAN.L: Quote, Profile, Research, Stock Buzz), HSBC (HSBA.L: Quote, Profile, Research, Stock Buzz), Royal Bank of Scotland (RBS.L: Quote, Profile, Research, Stock Buzz) and BNP Paribas (BNPP.PA: Quote, Profile, Research, Stock Buzz) fell between 1.1 percent and 8 percent. Defensive drug makers led the risers. AstraZeneca (AZN.L: Quote, Profile, Research, Stock Buzz), GlaxoSmithKline (GSK.L: Quote, Profile, Research, Stock Buzz) and Sanofi-Aventis (SASY.PA: Quote, Profile, Research, Stock Buzz) were up between 1.2 percent and 2.5 percent. Across Europe, the FTSE 100 index .FTSE was down 1 percent, Germany's DAX .GDAXI was down 1.3 percent and France's CAC 40 .FCHI was down 0.3 percent. (Additional reporting by Christoph Steitz; Editing by Andrew Macdonald)

Source