By Sara Sjolin, MarketWatch

LONDON (MarketWatch) -- U.K.'s FTSE 100 index rose for the first time in three days on Thursday, as heavyweight companies like Rio Tinto PLC and HSBC Holdings PLC advanced after corporate-related news.

The FTSE 100 gained 0.2% to close at 6,810.27, partly recovering from a 0.5% loss on Wednesday.

Helping lift the benchmark, Rio Tinto PLC (RIO) picked up 1.5% after Standard & Poor's Ratings Services revised the outlook on the miner to stable and said the it had reported strong 2013 results with credit metrics above expectations.

HSBC Holdings PLC (HSBC) advanced 1.4% after the heavyweight bank confirmed its in discussions with Meezan Bank Ltd. to sell its operations in Pakistan.

Shares of Reed Elsevier PLC put on 1.6% after the publishing firm reported a rise in full-year earnings and raised its dividend.

Shares of British American Tobacco PLC (BTI) gained 1.4% after the company reported a small rise in full-year profit and said it expects a gradual improvement in the economic environment.

Outside the main index, Man Group PLC rallied 14% after the investment manager said it swung to a full-year profit in 2013 and laid out plans to repurchase $115 million of its ordinary shares to return surplus capital to shareholders.

On a more upbeat note, shares of Royal Bank of Scotland Group PLC (RBS) topped the list of decliners, sliding 7.7%, after the 81% state-owned lender posted a loss of GBP9 billion ($15 billion) for 2013 and announced a plan to cut GBP5 billion in costs over the next few years.

RSA Insurance Group PLC lost 4% after the insurer launched a GBP775 million rights issue to strengthen its balance sheet. The company also reported a sharp decline in operating profit, which is a key measure in the insurance industry.

WPP PLC slumped 3.5% after the advertising giant said it missed its margin target for 2013. The slide in many emerging-market currencies against the pound weighed on profit in the second half and particularly in the last quarter of the year, the company said.

Another insurer, Standard Life PLC , lost 0.9% after the company reported a 30% drop in full-year profit.

Aviva PLC gave up 0.8% after the insurer said it has appointed Monique Shivanandan as chief information officer.

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