* FTSEurofirst 300 tumbles 3.8 percent
* Lehman bankruptcy filing hits stock markets
* Commodities slip; weaker crude, metals prices also weigh
By Atul Prakash
LONDON, Sept 15 (Reuters) - European shares slumped on Monday as nervousness gripped the market after Lehman Brothers <LEH.N> filed for bankruptcy protection and a newspaper reported that AIG <AIG.N> sought $40 billion from the Federal Reserve.
By 0843 GMT, the FTSEurofirst 300 <
> index of top European shares was down 3.8 percent at 1,118.10 points, its lowest in nearly two months. It is down 26 percent this year.Out of 314 shares traded on the index, 311 were down.
Lehman filed for bankruptcy protection, after trying to finance too many risky assets with too little capital, making it the largest and highest-profile casualty of the global credit crisis. [
] Its shares <LHMH.F> plummeted 80 percent in Frankfurt.Financial market woes continued with American International Group <AIG.N>, working to stave off rating downgrades and shore up the capital of its holding company, made an unprecedented approach to the U.S. Federal Reserve seeking $40 billion in short-term financing, the New York Times said. AIG officials did not immediately respond to requests for comment.[
]Banks topped the weighted losers list, with BNP Paribas <BNPP.PA>, Credit Agricole <CAGR.PA>, Dexia <DEXI.BR>, Fortis <FOR.BR> and Societe Generale <SOGN.PA> down between 6 and 9 percent.
The DJ Stoxx European banking index <.SX7P> and European insurance index <.SXIP> were down 5.4 percent and 5.9 percent respectively.
"This is a perfect storm in a perfect storm. There are two ways of looking at it: one, as financial Armageddon, the other as a dose of realisation of the level of complexity of the problem people are dealing with," said Justin Urquhart Stewart, investment director at 7 Investment Management.
"It's a return to pure capitalism, the survival of the fittest -- the government can't, and won't, bail everybody out." Britain's FTSE <
> fell 3.7 percent, Germany's DAX < > lost 3.6 percent and France's CAC < > fell 4.5 percent.FINAL CLEAN UP?
Bank of America Corp <BAC.N> agreed to buy Merrill Lynch <MER.N> in an all-stock transaction that Bank of America said is worth $50 billion. [
]A newspaper reported on Sunday that Swiss bank UBS <UBSN.VX> would have to write down another $5 billion on its risky investments in the second half of the year. Its shares were down 8.4 percent.
"It can be the final clean up, but you have a risk within the financial system to see a lot of downgrading and losses. Beyond this point, my concern is the real economy," said Valerie Plagnol, chief strategist at CM-CIC Securities, in Paris.
"We are faced with quite a dramatic credit crunch ... the fact that the central bank is widening its collateral to include stocks may prove to bring some support to the market, but I don't know. The Fed is really doing its best to avoid any major crash."
The Federal Reserve took new steps on Sunday to ease trading disruptions. The Fed said it would begin accepting equities as collateral for emergency loans for the first time ever, and said it would increase the amount of Treasury securities it auctions regularly under one of its lending programs. Commodity stocks also fell, hit by a broader sell off in the market and falling prices of metals and crude. Key base metals fell between 0.3 and 2.7 percent, while crude tumbled below $100 a barrel to a six-month low.
BP <BP.L>, Royal Dutch Shell <RDSa.L>, gas producer BG Group <BG.L> and Tullow Oil <TLW.L> shed between 2.3 and 5 percent.
BHP Billiton <BLT.L>, Anglo American <AAL.L>, Vedanta Resources <VED.L>, Lonmin <LMI.L>, Kazakhmys <KAZ.L>, Xstrata <XTA.L>, Antofagasta <ANTO.L> and Rio Tinto <RIO.L> slipped between 4.4 and 6.3 percent. BASF <BASF.DE> fell 4.5 percent after the world's biggest chemicals group said it planned to take over Swiss specialty chemicals company Ciba <CIBN.VX> to strengthen its position in that speciality business. [
]. But Ciba jumped 27 percent, a rare European gainer.A number of Asian markets including Japan and Hong Kong were closed on Monday for holiday. (Editing by Sue Thomas)