Four stocks, namely Bandhan Bank, Hindustan Copper, SAIL, and ZEEL, have been placed under the futures and options (F&O) ban list by the National Stock Exchange (NSE). This ban restricts the opening of fresh positions in these stocks' derivative contracts as they've exceeded 95% of the market-wide position limit. However, trading in the cash market remains unaffected. Investors are advised to manage existing positions accordingly, as any increase in open positions may lead to penalties. Stay informed about daily updates as the NSE revises the ban list regularly.