The stock tanked 5.09 per cent to settle at Rs 2,663.45 on the BSE. During the day, it lost 5.74 per cent to Rs 2,645.05.
At the NSE, it was down 4.90 per cent to Rs 2,667.50 at close.
The company's market capitalisation dipped by Rs 2,851.23 crore to Rs 53,185.77 crore.
The stock was the top loser among the blue-chips on both Sensex and Nifty.
"In a major initiative towards diversification into fast growth areas, the BML Munjal-led Hero Group has divested seven million equity shares in its flagship company Hero MotoCorp Ltd," Brij Mohan Lall Munjal-led Hero Group said in a statement.
Following the sale of seven million equity shares, the over USD 5 billion Hero Group still holds a significant stake of over 36 per cent in the company, the statement added.
According to information available with BSE, the promoter stake in Hero MotoCorp stood at 39.92 per cent at the end of December 2014.
