Cairn India's scrip tanked 5.69 per cent to Rs 326 on the BSE.
On the NSE, it was down 5.8 per cent to Rs 325.50.
Cairn India had yesterday reported a 65 per cent drop in its first quarter net profit after booking a one-time depreciation charge on new accounting rules, and said it will invest USD 200 million in developing a gas find in predominantly oil-rich Rajasthan block.
Net profit in the April-June quarter fell 65 per cent to Rs 1,093 crore, or Rs 5.76 a share, from Rs 3,127 crore, or Rs 16.36 a share, in the same period a year ago, the company had said in a statement.
The drop in net profit is "primarily due to change in method of depreciation from Straight line method (SLM) to Unit of production," it had said.