Shares of Bajaj Auto plunge by 4.97 per cent to Rs 2,422.65 on BSE.
On NSE, it lost 5.11 per cent to Rs 2,420.
The stock was the top loser on Sensex and Nifty indices.
Bajaj Auto today reported a 8.59 per cent decline in total sales in October at 3,52,822 units as against 3,86,017 units in the same month last year.
Motorcycle sales during the month declined 8.36 per cent to 3,08,733 units as against 3,36,923 units in October last year, the company said in a statement.
In the broader market, the BSE benchmark index Sensex was trading at 26,451.58, down 205.25 points at 1205 hrs.