Leading private sector lender ICICI Bank [Get Quote], which has lost its position as the country's most valued bank to state-run State Bank of India [Get Quote], said on Friday that "malicious rumours" are being spread to hammer down its share price.

"We are seeing malicious rumours completely without any basis at all and done in a consistent manner ... so clearly there is something much beyond just banking in this," ICICI Bank chief K V Kamath told to a private TV channel.

"We are clearly seeing concerted short-selling activities... We do not know who is responsible for this," he added.

ICICI Bank's share price has plummeted by nearly 15 per cent or more than Rs 100 per share in the past ten days.

On Thursday, ICICI Bank's market value dipped below that of public sector major SBI. Its market capitalisation has dipped to near Rs 64,000 crore (RS 640 billion), against close to Rs 1,00,000 crore (Rs 1,000 billion) for the public sector banking major SBI.

The bank had said in a statement earlier in the week that rumours were being spread that some of the top management of the banks were selling their shares. "These rumours are baseless and irresponsible, and no shares have been sold by members of top management of the bank during the current year," it added.

However, the impact of the collapse of iconic Lehman Brothers will be felt on the ICICI Bank as its UK subsidiary had an exposure of about Rs 375 crore (RS 3.75 billion) in bonds of the US-based investment banker.