Special quotations are to recognize the price of the lowest (highest) ask (bid) as the closing price of the day in case where there is no trade matched until the closing of the regular session but exist a lower (higher) ask (bid) than the base price for the day. As such, the special quotation is adopted as the base price for the next day.
As the KRX market has daily price limits, special quotations are needed to reflect the market trend to the stock price. For instance, if important information arises for a security, there may be one-sided orders only and thus no order matching. In this case, unless the one-sided orders are recognized, the daily price limits are kept unchanged and applied the next day, which prevents the material information from being reflected in the share price.
Meanwhile, when the price of preferred stocks is 2 times higher than the price of its common stocks, bid quotations are not construed as the special quotation price.