More than half of investors' funds have been recovered nearly four years after Bernard Madoff's arrest for running the biggest Ponzi scheme ever, the Wall Street Journal reported today. Trustee Irving Picard said Monday that he recovered, or reached deals to recover, more than $9.2 billion of the $17.3 billion in principal that investors lost as a result of Madoff's scheme, which landed him a 150-year prison sentence. Picard said that he collected $115.3 million by settling 18 cases between April 1 and Sept. 30. During that six-month period, Picard paid about $2.5 billion to Mr. Madoff's investors, bringing the total compensation they have received to $3.7 billion.