In what may turn out to be one of the biggest scams in the countrys corporate history, Delhi-based Punjab National Bank-PNB said on Wednesday it had been defrauded of about Rs 114 billion by jeweller Nirav Modi, his maternal uncle Mehul Chinubhai Choksi, and other relatives through a clutch of companies they own. The countrys second-largest public sector bank-PSB said two of its employees were involved in the scam, where the banks core banking system was bypassed to raise payment notes to overseas branches of other Indian banks, including Allahabad Bank, Axis Bank, and Union Bank of India, using the international financial communication system, SWIFT.