Deutsche Boerse and NYSE Euronext have extended the termination deadline for completion of their planned merger to March 31 next year from December 31 as they seek to convince European regulators to back the $9 billion deal which they agreed to on February 14th. The extension comes after months of frantic lobbying by the merger partners as they try to convince European anti-trust authorities in Brussels to approve the combination -- the last hurdle to the deal.  European authorities are fearful the merged entity would have a monopoly in European futures and options and have sought remedies from the exchanges, which between them have over 90 percent of European trading, to address this concern. The exchanges have offered several concessions including spinning-off parts of NYSE's futures trading business , offering open-access to D.Boerse's clearing unit to rival exchanges and assurances that derivatives trading fees would be capped for three years after the deal.  But European regulators last week showed no signs of buying these arguments, fuelling speculation the exchanges would look to bypass the anti-trust team and focus their lobbying on competition commissioner Joaquin Almunia. Approval by the European Commission is the last major hurdle for what would be the largest exchange merger in history as both exchange shareholders and the U.S. anti-trust authority have approved the deal.  The Commission is scheduled to decide whether to approve the merger by February 9, but a decision could come by the end of January.  [Reuters 12/28/11].