The bank's scrip plunged 5.47 per cent to Rs 78.55 on the BSE.
At the NSE, the stock lost 5.47 per cent to Rs 78.55.
CBI has started a preliminary enquiry into the Rs 950 crore alleged bad loan given by IDBI Bank to Kingfisher Airlines ignoring the company's negative credit ratings and net worth.
"It was first exposure to the bank. There was no need for the bank to take the exposure outside the consortium when already other loans were getting stressed," a senior CBI official probing the matter had said on Saturday.
The debt-laden airlines has stopped operations since October 2012.