By Michael Taylor

LONDON (Reuters) - The FTSE 100 reversed early gains on Thursday as commodity stocks weighed, but Cairn Energy topped the leaderboard after a successful share placement.

Oil explorer Cairn gained 3 percent after announcing it had completed the placing of Cairn India shares on the Bombay Stock Exchange and raised 37 billion Indian rupees (430 million pounds).

Other oil stocks weighed however, as U.S. crude oil prices fell to $58 after a buildup in crude stocks in the United States. BP was down 0.7 percent and Royal Dutch Shell fell 0.6 percent.

Fresh concerns about a global economic slowdown in 2007 hit miners. Antofagasta dropped 1.1 percent and Vedanta lost 2.8 percent.

The banking sector led the losers, as some traders said the Bank of England's November interest rate had finally begun to hit the markets. Barclays dropped 0.5 percent and HBOS fell 1.5 percent.

But with little economic data expected throughout Thursday and the closure of Wall Street because of the Thanksgiving Day holiday, traders were predicting a slow day of trading.

"The rally really seems to have run out of steam for now, especially in light Thanksgiving volumes," said Chris Iggo strategist at Axa Investment Managers. "But I think we should wait until next week as some decent economic news could give it a kick."

"With signs of a slowing global economy the UK market suffers because it is weighted towards two sectors - oil and mining - which are heavily geared to the economic cycle," he added.

By 11:52 a.m., the FTSE 100 was down 35.4 points or 0.5 percent at 6,124.9.

BROKER UPGRADES FEATURE

ICI ICI.L climbed 2.9 percent after an upgrade from three brokers, and on bid speculation and positive sentiment following the sale of its flavours and fragrance business Quest International on Wednesday.

Vodafone added 1.1 percent on news that Swisscom is to enter talks to repurchase its 25 percent stake in Swisscom Mobile, potentially marking the British company's exit from the partnership. It also benefited from several broker upgrades.

Enterprise Inns also added 1.6 percent on various upgrades.

Tobacco shares also featured on the upside, after the top European Union court ruled that individuals must still pay duty on tobacco in their own country even if they order the product from another EU state. Imperial Tobacco climbed 1.7 percent and Gallaher Group GLH.L added 0.8 percent.

Building materials firm Wolseley dipped 2.3 percent on talk that a slowdown in the U.S. housing sector could be worse than feared, traders said.

"There is a growing realisation that the U.S. housing downturn is going to be deeper and last for longer than had been expected," one trader added. Shares in rival Hanson HNS.L were down 2.4 percent.

Water utility Kelda Group KEL.L fell 2.7 percent on a Citigroup downgrade and after bid speculation subsided.

Among midcaps, kitchens and furniture maker Galiform was up 3.1 percent after it confirmed rising sales in a statement, following the disposal of its loss-making furniture retail unit MFI.