By Sudip Kar-Gupta

PARIS (Reuters) - Societe Generale's missed forecasts with a third quarter net profit that more than doubled from a year ago and the bank said the economic environment remained uncertain, following a deep financial crisis.

Like other banks that have reported in the past few weeks, such as Credit Suisse and Deutsche Bank, investment banking results powered the profit line while the bank added to provisions as many financial institutions expect bad loan to rise in 2010.

Net profit rose to 426 million euros ($623.2 million) euros from 183 million a year earlier, mainly due to the fact that SocGen's investment banking arm turned in a profit compared to a loss a year earlier.

A Reuters poll of 10 analysts had given an average net profit forecast of 481 million euros.

SocGen's results kicked off the third quarter earnings season for France's banks, with larger rival BNP Paribas also expected to post higher earnings on Thursday.

However, although many of the world's top banks have posted higher profits over the last month, doubts remain over provisions in the sector and the global economic uncertainty.

On Tuesday, UBS reported a third quarter loss and the British government injected yet more taxpayers' money to help part-nationalised banks Royal Bank of Scotland and Lloyds.

SocGen has been steadily recovering since a 4.9 billion euro trading loss in January 2008 which it blamed on unauthorised deals carried out by Jerome Kerviel, a former junior trader at the bank.

SocGen shares closed down 4.3 percent at 43.65 euros on Tuesday, giving the bank a market capitalisation of around 32 billion euros.

The stock has risen around 30 percent so far this year, less than a 45 percent gain in the DJ Stoxx European banking index.

(Editing by Marcel Michelson)

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