At market close, Reliance Industries Ltd (RIL) market capitalisation (m-cap) zoomed to Rs 10,01,555.42 crore on BSE.
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.
Reliance Industries Ltd (RIL) had on Monday raced past TCS to become the country's most-valued firm by market valuation.
At close of trade on Monday, RIL's m-cap stood at Rs 8,19,073.62 crore, which is Rs 7,226.43 crore more than that of TCS.
Revision in the outlook follows RIL announcing plans to sell a 20 pc stake in its oil-to-chemical division to Saudi Aramco.
RIL also entered a deal with BP to sell 49 pc stake in its fuel marketing business in India for USD 1 billion.
Rivals face heat; shares of telecom, multiplex players plunge.
The oil-to-telecom giant saw its scrip jump 9.72 per cent to close at Rs 1,275 on the BSE.