The stock plunged 6.67 per cent to Rs 463.90 at the BSE.
Tata Motors was the biggest loser among 30 Sensex stocks.
On the NSE, it fell by 6.84 per cent to Rs 463.55.
Tata Motors' March quarter net profit declined by 56.2 per cent to Rs 1,716 crore due to massive asset write-downs, 220-million pound forex loss and poor show by its cash-cow British arm.
The company had reported a consolidated net profit of Rs 3,918.29 crore in the same quarter previous fiscal.
The same rose to Rs 13,387 crore from Rs 11,078 crore for the full financial year.