The scrip, which opened at Rs 20, plunged nearly 15 per cent to Rs 18.80 on the BSE. It had closed at Rs 22.05 on Tuesday.
On the NSE too, the company's shares fell 15 per cent to Rs 18.80 and had touched a low of Rs 17.80. It opened at Rs 19.95 after closing at Rs 22.10 yesterday.
The Securities Exchange and Board of India (Sebi) has banned Ruchi Soya Industries and National Steel and Agro Industries from the securities market for alleged fraudulent and manipulative in trading in castor seeds at the NCDEX.
The two companies have been barred from "buying, selling or dealing in the securities market, either directly or indirectly, in any manner whatsoever, till further directions", Sebi said on Tuesday.
In his order, Sebi Whole Time Member Rajeev Kumar Agarwal said that prima facie the acts and omissions of Ruchi Soya Industries and National Steel and Agro Industries have not only disturbed market equilibrium but also indicate manipulative and fraudulent design to form a cartel and corner the castor seed market.