Greece\'s leading lender National Bank said Monday that it has increased its capital by one billion euros, boosting its defences ahead of a controversial write-down of government bonds. NBG said that a sale of preference shares to the government brought in one billion euros ($1.3 billion) as part of wider efforts to bolster the banking system so it can help drive the recession-hit economy. The move should increase NBG\'s Core Tier 1 capital ratio -- a key measure of how much money it holds in reserve as a proportion of assets -- to more than 11 percent from 9.5 percent at end-December. In December, NBG said it would raise the money from the state support fund set up in 2008 at the height of the global financial crisis and which closed at the end of the year. NBG last month said it lost 1.346 billion euros in the first nine months of the year after factoring in a write-down of its Greek government bond holdings, part of a second rescue package for the debt-stricken country. The Greek government is in talks with private debt holders with the aim of securing a 50-percent write-down on its maturing obligations, meaning the banks have to take substantial losses on their holdings of government bonds. The October EU debt accord -- after an initial May 2010 package proved too little -- also sets aside 30 billion euros to help the Greek banks cope with the resulting losses on their bond holdings. In contrast to common shares, the terms of preferred shares can be varied to limit voting rights or the total stake they represent.