The scrip lost 5.77 per cent to Rs 87.30 on BSE.
At NSE, the stock tumbled 5.60 per cent to Rs 87.55.
The telecom company yesterday posted a loss of Rs 815.9 crore in the first quarter ended June 30, impacted by sustained pressure from disruptive tariffs of Reliance Jio.
This is the third straight quarter loss for the Aditya Birla group firm as it has not been able to recover from the pressure of aggressive tariff war triggered by Mukesh Ambani- led Reliance Jio Infocomm.
Total revenue of Idea also declined by about 14 per cent to Rs 8,181.7 crore in the reported quarter from Rs 9,552.4 crore in the corresponding period of 2016-17.