The government's offer-for-sale for more than 4.75 crore Hindustan Zinc Ltd (HZL) shares to institutional investors over-subscribed on Wednesday, with institutional buyers putting bids worth close to Rs 3,400 crore. On the first day of the two-day OFS, bids came in for over 6.69 crore shares, which is 1.41 times the total of 4.75 crore shares on offer for institutional buyers.