Shares of ICICI Bank plunged nearly 6 percent today, wiping out Rs 10,452.84 crore from its market valuation amid controversy over alleged conflict of interest involving the lender and Videocon Group. The stock tumbled 5.93 per cent to end at Rs 261.90 on BSE. Intra-day, it dived 7 per cent to Rs 258.90. At NSE, the stock plunged 5.92 percent\u00a0 to close at Rs 261.85.Following the sharp fall, the company's market valuation eroded by Rs 10,452.84 crore to Rs 1,68,344.16 crore at close. The stock was the worst performer among blue-chips on both Sensex and Nifty indices today.On the volume front, 25.51 lakh shares of the company were traded on BSE and over 7 crore shares changed hands at NSE during the day. Shares of Videocon Industries also fell 4.97 per cent to Rs 12.42 - the lowest trading permissible limit for the day - on BSE. With ICICI Bank embroiled in a controversy over alleged conflict of interest involving its CEO Chanda Kochhar, market regulator Sebi has begun looking into the matter for any possible disclosure and corporate governance-related lapses. Earlier last week, some media reports mentioned about alleged involvement of Kochhar and her family members in a loan provided to Videocon Group on quid pro quo basis.The CBI has questioned a few officials of ICICI Bank as part of a preliminary enquiry to find out if any quid pro quo was involved in the bank giving Rs 3,250 crore loan to the Videocon Group in 2012.ICICI Bank said its board will meet today to review insolvency cases before National Company Law Tribunal, and other routine matters. This is the first time the board will meet after the alleged controversy broke out. The bank said that the board meeting is routine in nature.Meanwhile, in a separate filing, the bank said it has not received any communication from the Enforcement Directorate relating to enquiry into the loan to Videocon group. "We confirm that ICICI Bank has not received any communication from the Enforcement Directorate relating to any enquiry into Videocon group as on date," it said. The bank further said it was not aware of any information that had not been announced to the exchanges under regulations. The bank was asked by stock exchanges to clarify on the media report.