Shares of Hindustan Zinc dropped as much as 6.3% on Wednesday to Rs 455.35 on the BSE, deepening a six-session slide that has wiped out nearly 15% of its market value. The selloff comes just as the company is laying out a multi-year expansion plan, sparking a divide amongst Dalal Street brokerages over whether the current correction is a buying opportunity or a sign to stay cautious.