Spain rejects U.S. extradition of 'London Whale' supervisor

By Sonya Dowsett MADRID (Reuters) - Spain on Thursday rejected a U.S. extradition request for Javier Martin-Artajo, an ex-JP Morgan Chase & Co executive indicted over the "London Whale" scandal which led to over $6 billion (4 billion pounds) in trading losses in 2012. The case is the latest to show the complexity of transatlantic financial inquiries after a British trader accused of contributing to the 2010 Wall Street "flash crash" began a fight against extradition to th