The steep fall was mainly triggered over concerns that certain provisions in the '2014-19 Tariff Regulations' -- notified on February 21 -- could have some negative impact on the company.
The regulations were notified by the Central Electricity Regulatory Commission (CERC).
Reacting to the development, shares of the company opened on a weak note on the BSE and slumped by 11.50 per cent to its 52-week low level of Rs 116.95 in morning trade today.