At market close, Reliance Industries Ltd (RIL) market capitalisation (m-cap) zoomed to Rs 10,01,555.42 crore on BSE.
On the BSE, Reliance Communications's shares rose 4.55 per cent to 69 paise apiece.
From the top-10 pack, only RIL, HDFC and SBI witnessed gains in their market valuation for the week ended Friday.
RIL became the first Indian firm to hit the Rs 9 lakh crore market valuation mark in intra-day trade.
The valuation of TCS tumbled Rs 26,900.6 crore to Rs 6,22,401.90 crore, making it the top loser among the pack.
RIL, HUL, HDFC, ITC, Infosys, HDFC Bank and SBI were the other firms which witnessed a rally in their market capitalisation.
The m-cap of Reliance Industries Ltd zoomed Rs 28,494.36 crore to Rs 8,57,303.03 crore, the most among the frontline entities.
The company in an emailed statement said: "There has been no transaction of purchase of shares".
The acquisition was pursuant to a scheme of arrangement not directly involving Reliance, the filing said without giving details.
Reliance and BP plan to split Niko's share in proportion to their existing shareholding in the block.