(ANSA) - Trani, January 23 - A probe has been launched into allegations of fraud in derivatives trading against top officials of the BNL bank, prosecutors said Thursday. Under investigation are the President of the board of directors of BNL, Luigi Abete, Vice-President Sergio Pietro Erede, and Chief Executive Officer Fabio Gallia along with 13 others, prosecutors said. It is alleged senior officials were all involved in complex financial transactions including derivatives valued at three million euros, and induced local bank branches to sell these to customers between 2008 and 2012. According to prosecutors, the deals were organized so as to benefit the bank rather than the customers and constituted aggravated fraud that continued over a period of time. One client of BNL in the southern city of Corato in Bari province, Malo Ltd., was said to have suffered losses of about 600,000 euros. Prosecutors in the city of Trani, about 400 km south of Rome, are specialists in investigating financial crimes. Currently they are also investigating other unrelated finance cases including problems at MPS bank; a probe of the possible manipulation in recent years of Euribor, the euro-priced counterpart of scandal-hit Libor interbank lending rates; and activities of the major rating agencies including Moody's, Standard and Poor's, and Fitch.