By Dominic Lau
LONDON, Feb 15 (Reuters) - Britain's FTSE 100 <
> index dipped by mid-session on Friday, led by banks and oil shares, but heavyweight GlaxoSmithKline <GSK.L> offered some support after billionaire Warren Buffett invested in the drugmaker.At 1130 GMT, the FTSE 100 <
> was down 18.9 points, or 0.3 percent at 5,860.4, well off its day's high of 5,915.0. The UK's blue-chip index has advanced 1.3 percent so far this week, but is down 9 percent for the year on fears of a U.S. recession."The...fact that the U.S. economy is not looking good outweighs any benefit from interest rate cuts over there," said Mark Priest, a trader at TradIndex.
"A lot of banks are reporting over the next couple of weeks, and people will be keen to see what they will come up with," he said. "It's going to be volatile... we haven't really had any good news."
Banks fell, with Barclays <BARC.L>, Lloyds TSB <LLOY.L>, HBOS <HBOS.L>, Standard Chartered <STAN.L> and Alliance & Leicester <ALLL.L> down between 0.7 and 3.6 percent.
A six-notch rating cut from Moody's Investors Service on FGIC Corp's bond insurance arm meanwhile sent investors a fresh reminder of the credit turmoil that has hamstrung the financial markets.
Citi said in a note that Swiss bank UBS <UBSN.VX> could need up to $18 billion in additional write-downs in 2008. The bank has already written down $18 billion in losses in 2007 due to its exposure to U.S. subprime mortgages and linked assets.
BP <BP.L> dipped 1.3 percent after ABN AMRO cut its price target on the oil major by 7.9 percent. Royal Dutch Shell <RDSa.L> eased 0.7 percent and Cairn Energy <CNE.L> shed 1.5 percent.
But GSK rose 1.6 percent after Berkshire Hathaway <BRKa.N>, the holding company controlled by Buffett, said it owned 1.51 million American depository receipts of the drugmaker.
Fellow drugmaker AstraZeneca <AZN.L> added 0.5 percent.
In testimony to U.S. Congress on Thursday, Federal Reserve Chairman Ben Bernanke held the door open to more interest rate cuts to help the struggling U.S. economy, but said the central bank expected growth to pick up later in the year.
U.S. industrial production and University of Michigan consumer sentiment data from 1415 GMT will give investors a further gauge of the strength of the world's largest economy.
GO-AHEAD DIVES
Bus and rail firm FirstGroup <FGP.L> lost 5.2 percent to top the losers' list on the FTSE 100 after fellow bus and train operator Go-Ahead <GOG.L> warned about its rail business. Mid-cap Go-Ahead plunged nearly 16 percent.
Miners were mostly firmer, with BHP Biliton <BLT.L>, Rio Tinto <RIO.L>, Kazakhmys <KAZ.L>, Vedanta Resources <VED.L> and takeover target Xstrata <XTA.L> up between 0.1 and 2.7 percent. But Anglo American <AAL.L> and Antofagasta <ANTO.L> slipped.
A rating upgrade and price target hike from UBS also boosted Vedanta.
Also in the mid-cap, Tate & Lyle <TATE.L> advanced 2.3 percent after the sugar refiner and sweetener maker said profit before tax for the four months to end-January was marginally ahead of its expectations. (Additional reporting by Michael Taylor; Editing by Richard Hubbard)