Shares of Punjab National Bank (PNB) plunged over 8 per cent and hit their fresh 52-week low of Rs 102.10 in early trade on Tuesday after the state-owned bank said the amount of fraudulent transactions could be Rs 1,300 crore more than the current estimate of about Rs 11,400 crore.

The scrip was trading 8.40 per cent down at Rs 102.50 at around 10.55 am (IST) on the BSE. It opened at Rs 107.80 and touched a high and low of Rs 107.80 and Rs 102.10, respectively. Benchmark BSE Sensex rose 53.72 points, or 0.16 per cent, to 34,499.47 at around the same time.

PNB on February 14 had detected the scam involving billionaire jeweller Nirav Modi and associates who had allegedly acquired fraudulent letters of undertaking (LoUs) from one of the branches of the PNB for overseas credit from other Indian lenders.

In a filing to the BSE on Monday, the bank said the amount of unauthorised transactions could go up by more than Rs 1,300 crore.

“...We have to inform that quantum of reported unauthorised transactions can increase by USD 204.25 million (approximately),” PNB said.