CIL's scrip plunged 5 per cent to Rs 364.60 at the BSE.
On the NSE, it lost 5.1 per cent to Rs 364.20.
The blue-chip stock was the biggest loser among the front-line scrips on both the Sensex and Nifty.
In the country's biggest share sale ever, the government will sell up to 10 per cent stake in Coal India Ltd to raise about Rs 24,000 crore on Friday.
The disinvestment is expected to help government meet half of the Rs 43,425 crore revenue target from stake sale in public sector companies.
At yesterday's closing price of Rs 384.05, a 10 per cent stake sale will enable the world's largest coal producer to raise Rs 24,257 crore.