Indian Oil Corp (IOC) would raise up to 220 billion rupees ($2.66 billion) through a rights issue of shares, the state-owned refiner said on Friday.

Last month, Reuters reported that the Indian government had kicked off its plan to fund energy transition projects of three big state refiners — IOC, Bharat Petroleum Corp Ltd (BPCL) and Hindustan Petroleum Corp Ltd (HPCL) — in exchange for equity.

IOC, the country's top refiner, has not specified which projects the newly raised funds would target. It said it would give further details on the rights issue, including the price and timing, after a board approval.

Last week, BPCL had said it would raise $2.19 billion through a rights issue to help meet its "energy transition, net-zero and energy security objectives".

HPCL has not yet announced any plans to raise funds. The government is seeking a preferential allotment of shares from HPCL, Reuters had reported.

The three refiners together aim to invest 3.5-4 trillion rupees to achieve their net zero-emission goals by 2040.

Indian Oil also approved the formation of a joint venture for battery-swapping business in India as a private limited company with 50:50 collaboration between itself and Sun Mobility Pte Ltd Singapore, with IOC's equity investment of 18 billion rupees ($217.83 million).

Indian Oil's share price has gained nearly 30% so far this year, while HPCL's has risen over 30% and BPCL's roughly 18%.

In comparison, the benchmark Nifty 50 has gained almost 7%. ($1 = 82.6030 Indian rupees)

(Reporting by Varun Vyas in Bengaluru; Editing by Shilpi Majumdar)