The stock went down by 4.80 per cent to end at Rs 677.90 on BSE. Intra-day, it plunged 5.90 per cent to Rs 670.
On NSE, shares of the company dropped 5.20 per cent to close at Rs 675.70.
Tata Communications yesterday registered consolidated loss of Rs 250 crore in the July-September quarter of 2017-18, chiefly because of its investment in sister concern Tata Teleservices.
The company had posted profit of Rs 39.96 crore in the year-ago period.
"PAT (profit after tax) recorded negative at Rs 250 crore on account of additional provision of Rs 186 crore as per the contractual obligation to Tata Sons on the Tata Teleservices investment and due to other one-time exceptional provisions of Rs 27 crore," Tata Communications said in a statement.