Cairn India went up 3.54 per cent to Rs 187.15 on BSE.
On NSE, it gained 3.65 per cent to Rs 187.35.
Shares of Vedanta too climbed 2.82 per cent to Rs 189.20 on BSE.
India's largest private miner Vedanta Ltd headed by billionaire Anil Agarwal will merge Cairn India with itself in an attempt to cut debt.
Shareholders in Cairn India, the country's top private oil producer, will get one ordinary share and 7.5 per cent redeemable preference share of Vedanta Ltd with a face value of Rs 10.
Vedanta will use Rs 16,867 crore of cash lying with Cairn to pay off part of its Rs 77,752 crore debt.
Post-merger, London-listed parent Vedanta Resources' holding in Vedanta Ltd will drop to 50.1 per cent from 62.9 per cent.
