Update : May 12, 2011
A special quote is indicated whenever prices look likely to jump beyond the special quote renewal price intervals given in 'Is it possible for stock prices to jump suddenly, for example from 1,000yen to 1,100 yen?'. Special quotes are mechanisms to prevent short-term wild price fluctuations.
Special quotes can be indicated at any time during the trading session, whether it is before the opening price has been set or during Zaraba trading, if there is any likelihood of inappropriate price fluctuations, for example as a result of a major order imbalance between bids and offers. Special offer quotes are indicated when the next price is anticipated to be at a price lower than, and special bid quotes are indicated when the next price is anticipated to be at a price higher than, the given appropriate special quote renewal price interval.
Special quote information is publicly disseminated through the TSE market information system, thus notifying market participants of the order imbalance as soon as possible.
A special quote indicates to investors that there are orders beyond that price, and encourages them to place balancing orders on the other side of the order book. If such orders are placed, matched and executed, market equilibrium will have been achieved and the special quote will be removed. If on the other hand, no orders are received the special quote will be renewed every 3 minutes, until equilibrium is achieved.
For example, if a buy order is placed at 550 yen immediately after an execution price of 500 yen, a special bid quote of 510 yen (±10 yen as per table in 'Is it possible for stock prices to jump suddenly, for example from 1,000 yen to 1,100 yen?') will be indicated. If no offers are received at this price, the special bid quote will be raised to 520 yen after 3 minutes, and so on until equilibrium is achieved.