The State Bank of India (SBI) and its five associate banks have lost a total of Rs 5,881.20 crore in the said period. SBI, which reported 2,049 fraud cases, lost the majority of this money (Rs 3,461.74 crore), followed by State Bank of Hyderabad which lost Rs 876.43 crore and reported 139 fraud cases.

IDBI, which is also being probed in the Kingfisher Airlines case, has lost Rs 1,350.69 crore in the said period, while reporting 388 fraud cases.

The four banks headquartered in Karnataka — Syndicate, Corporation, Canara and Vijaya — have lost a cumulative 4,342.10 crore, with the highest lost by Canara Bank BSE -0.44 % (Rs 1,309.14 crore), which reported 334 cases of frauds.

The CBI, which is investigating the Syndicate Bank case, has registered a case under several sections of the IPC besides the Prevention of Corruption Act, indicating involvement of insiders.

The highest loss was reported in 2014-15 even as the year recorded the least number of fraud cases. PSU banks lost Rs 11,022.32 crore go down to 2,166 frauds.

In March last year, the CBI investigated a case against a private firm in Ahmedabad and its director after a joint complaint received from State Bank of India, Vijaya Bank and Canara Bank.

It was alleged that the firm expressing urgency for releasing the funds had got it released, pending execution of individual documents. Sources had pointed out that after the release of the money, the man disappeared from India.

In another case that year, an MD of a private firm from Bhopal was arrested after he went absconding in a case relating to alleged loss caused to State Bank of Indore. The CBI had said that he had conspired with officials at the bank and dishonestly & fraudulently obtained credit facilities on the basis of fake collateral securities.

Obtaining loans through fake documents is seen as a common modus operandi across cases, and investigators have often found involvement of insiders from the banks.