LONDON (BLOOMBERG) - Credit Suisse Group is seeking to push one of Sanjeev Gupta's key commodities-trading units into insolvency, presenting a new threat to his metal empire after the collapse of his biggest lender. The application to wind up Liberty Commodities was filed in the UK's insolvency court late Tuesday (March 30) by a unit of Citigroup. Citi was acting under instructions from Credit Suisse, according to a person familiar with the matter who asked not to be identified discussing private information. The move marks a dramatic turn for the worse in Mr Gupta's battle to secure the survival of his corporate empire. For several weeks since Greensill Capital collapsed into insolvency, Mr Gupta and his GFG Alliance have been searching for new financing while simultaneously trying to persuade his existing lenders to hold off. And in another blow for Mr Gupta's embattled empire, Morgan Stanley and ICBC Standard Bank, two lenders to GFG's aluminum smelter in Dunkirk, France, have started talks with potential buyers of their loan exposure to the group, according to people familiar with the matter. An unnamed lender sought to sell US$7 million of the debt at 15 per cent discount on W...