The right allotment of shares to high net worth individuals who had subscribed to the ONGC issue will take place by Wednesday morning.

MCS, registrar to the issue, said the reversal of entries and rightful credits of the shares allotted were in the process of being uploaded and would be completed by tonight.

Santosh Rateria, promoter of MCS, said the uploading would take place by Tuesday night. National Securities Depository Ltd officials, when contacted, said they had not yet received the credit files.

Meanwhile, the Securities and Exchange Board of India, as a matter of routine, is also making inquiries into what exactly went wrong at the registrar's end in order to ascertain whether it was a genuine human error or a failure in systems.

However, Sebi officials said they would allow the current rectification work to go uninterrupted before they commenced their enquiries.

On Monday morning after the ONGC shares had been allotted, it was found that MCS had made wrong credits to the demat accounts of high net worth individuals, clubbing them along with retail investors and giving them 100 per cent allotment -- that is, all the shares they had applied for.

Divestment Minister Arun Shourie on Monday had said the government would be looking into what had transpired exactly at the registrar's end.

Rateria said a software problem had led to the error. The shares which have been already been transacted as a result of the wrong allotments would be kept in abeyance for the moment.

Sources said that on the settlement date, April 1, everything would be ironed out since by that time the credits to the accounts would have already taken place.

The ONGC scrip on Tuesday closed down marginally lower at Rs 839.60, after hitting a high of Rs 846.50 and a low of Rs 820 during the day. Trading volumes on the BSE were of the order of 10.23 lakh (1.02 million) shares.