The public offer in which government plans to sell 5 per cent (427.77 million shares) was scheduled to open on July 5 and close on July 8.
"To keep those timelines, three independent directors needed to fulfil Sebi's listing requirement should have been appointed by June 14," a senior government official said.
After the appointments are made, ONGC will need three full working days to prepare papers for filling with the market regulator.
As per the July 5 timeline, ONGC was supposed to file red herring prospectus for the follow-on public offer by Friday (June 17) and roadshows to promote the public offer was to star soon after that.
"The file for appointment of three independent directors on ONGC board is with the Prime Minister's Office. We haven't heard from the PMO till now," the official said.
The share sale was originally planned to happen in 2010-11 but was deferred to April 5 as the company did not have adequate number of independent directors on its board to meet the market regulator Securities and Exchange Board of India's listing norm.
It then listed for July 5 but will have to be deferred again over the same reason.
ONGC does not meet Sebi's listing norm of having an equal number of functional and independent directors and the government had previously planned to withdraw both its nominee directors on the board to push the FPO through.
But the move would have led to ONGC losing its coveted Navaratna status, which gives the company board autonomy to approve an investment of any size on its projects and powers to invest up to Rs 1,000 crore (Rs 10 billion)
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