Bangalore: In an effort to curb fraudulent use of credit cards, cardholders may be asked to furnish the proof of identity while making big-sum purchases. The move has been encouraged by banks issuing credit cards and associated merchants like Visa, MasterCard to check deceptive use of credit cards. Indicating the loss burden due to fraudulent transactions, a bank official said, "The fraud to sales ratio in India is at 0.12, which means of every 100 spent, 12 paise is lost." Hit hard by the mounting losses due to increasing number of credit card frauds, most banks have asked merchants to ask for proof of identity for verification when a customer makes a high-value purchase using a credit card. Praveen Bansal, Deputy General Manager, Union Bank of India said, "We have written to all our credit and debit card holders to register their mobile phone numbers with the bank. For transactions over 500 on credit or debit cards, we send an SMS to the customer giving details of the transactions." Another bank, the Industrial Development Bank Of India (IDBI) has instructed the merchants to ask customer making purchases on credit cards of amount exceeding 10,000, to furnish ID proof. According to RBI, on May 31, 2009 there were 48.42 million credit cards in use in India, with outstanding amount of 9,748.31 crores, but the overall credit card business is on downside.