CIL's shares tanked 3.9 per cent to Rs 360.50 at the BSE.
On the NSE, it slipped 3.82 per cent to Rs 360.60.
The government's 10 per cent stake sale in blue-chip Coal India, to raise an estimated Rs 22,600 crore, began today.
The total issue of 31.58 crore shares got bids for over 45.02 lakh shares by 1005 hours, as per the NSE data.
The retail category of 12.63 crore shares got bids for over 7.20 lakh shares (0.57 per cent). The general category of over 50.53 crore shares were subscribed nearly 0.75 per cent.
The government is selling 31.58 crore shares, or five per cent stake, through a public offer, with an option to sell another 5 per cent.