Tata Mutual Fund will invest Rs292 crore while SBI Fund Management will invest Rs200 crore, the people mentioned above said on condition of anonymity.

The CCDs will mature in three years and carry a fixed coupon payment to be paid annually. OPAL is the petrochemicals arm of state-run Oil and Natural Gas Corp. Ltd (ONGC).

“It is proposed to raise funds through issuance of CCDs with backstopping from ONGC for payment of principal and coupon amount to meet the equity requirement,” said the first of the two people mentioned above.

The CCDs will be sold in a single tranche and the allotment is to be completed in 20 days. ONGC holds 49.36% in OPAL, GAIL (India) Ltd 49.21% and Gujarat State Petroleum Corp. Ltd (GSPC) 1.43% stake, as of March 2016.

An email sent to ONGC Thursday was not answered till press time.

To meet its equity requirement, OPAL has in the past raised Rs7,286 crore through private placement of CCDs in two tranches of Rs5,615 crore in July 2016 and Rs1,671 crore in May 2017 with ONGC’s support.

OPAL operates a $4.5 billion mega petrochemicals complex in the Dahej special economic zone (SEZ) in Gujarat.

The plant will annually produce 1.4 million tonnes of polymers such as linear low density polyethylene and high density polyethylene, polypropylene and 500,000 tonnes of chemicals like benzene, butadiene and pyrolysis gasoline, among other products.

ONGC, GAIL and GSPC have also been holding talks to bring in private partners into the company. The three promoters will subscribe up to 50% equity, with the rest to be tied up through a mix of strategic or private equity investors and public issue to keep it as a private sector entity.