FACTBOX: More questions than answers after SocGen fraud

(Reuters) - The biggest rogue trader scandal in history hit French bank Societe Generale on Thursday, with a junior employee accused of a fraud costing $7 billion.

But the crisis has raised more questions than answers about the reasons for the fraud, how it was implemented and escalated, and what it means for the banking industry.

Here are some key issues still unknown:

--WHERE IS JEROME KERVIEL?

The 31-year-old has been named by banking sources as the man behind the fraud, although SocGen has still not confirmed the identity of the rogue dealer.

A photograph of an unsmiling Kerviel has been carried by the world's media, but none have tracked him down. Dubbed "the man who blew up the bank" by French daily Le Parisien, he has been variously described as a genius and a troubled introvert.

A lawyer claiming to represent Kerveil said he was not on the run and was ready to cooperate with investigators.

"I am sure he is very scared," Nick Leeson, the rogue trader who was at the centre of similar controversy when he cost British bank Barings $1.4 billion over a decade ago, told Irish media.

--DID KERVIEL ACT ALONE?

In the absence of Kerviel, conspiracy theories abound.

SocGen said the trader acted alone, but there was widespread speculation that fraud on such scale would have been impossible without some help. The trader and up to six supervisors above him have been fired.

--HOW WAS FRAUD ACHIEVED?

Positions on "plain vanilla" European stock market futures contracts were able to be hidden because the trader knew procedures after previously working in the back office, SocGen said.

He appears to have used false client names and faked hedging positions, but full details of how he ran rings around SocGen's sophisticated anti-fraud systems from a desk at headquarters may never emerge.

Also unclear is whether counterparties or clearing houses could have spotted the problems earlier and limited the scale of the crisis.

SocGen's loss was exacerbated because when it started unwinding positions on Monday stock markets were in a tailspin. Futures allow an investor to leverage a position, so SocGen many have had to unwind a 30-50 billion euro ($44 billion-$73 billion) position.