The Indian Depository Receipts (IDRs) issued by Standard Chartered Plc fell by 20% during the day as fresh regulatory norms barred investors from both redeeming the IDRs and converting them into shares of the bank that is listed on exchanges in London and Hong Kong.

During the morning trading session, the IDRs touched a new all-time low of Rs 91.75, before recovering partially. At 12 noon, the IDRs were trading at Rs 96.20 on the Bombay Stock Exchange (BSE). More than 11 million IDRs were traded in the first three hours of the session. On the National Stock Exchange (NSE), it was trading at Rs 96, down nearly 19%.

On Friday, the Securities and Exchange Board of India (Sebi) clarified that investors can redeem their IDRs only after one year of its listing and if the IDRs are "infrequently traded". The trading pattern of Standard Chartered IDRs clearly shows that it does not fall in the definition of illiquid IDRs as laid down by the regulator.

Sebi also clarified that fungibility of IDRs would not be allowed.

"After the completion of one year from the date of issuance of IDRs, redemption of the IDRs shall be permitted only if the IDRs are infrequently traded on the stock exchange(s) in India," said the Sebi circular.

IDRs are shares issued by foreign companies and are listed on the Indian exchanges. It basically gives Indian investors an opportunity to own a share of a foreign company. Currently, Standard Chartered Plc, which is listed on London Stock Exchange and Hong Kong Stock Exchange, is the only entity that listed its IDR in India.