Should an extraordinary situation arise, the Exchange, as a part of its market steering
activities, may take all measures it deems necessary to preserve the fairest and most
orderly trading possible. Further information in this regard can be found in the
Rule Book[pdf] and
Directive 3: Trading[pdf].
Intervention in the opening of trading
The Exchange may delay the opening of trading by a predefined amount of time if a number of
criteria are met.
If the theoretical opening price deviates sharply from the reference price, a Stop Trading
condition is automatically triggered and the opening is delayed by 5 or 15 minutes. The limits
for deviation and the length of time for which trading is stopped are set out in the Trading Guide.
Delayed Opening "No Quote"
If at the opening there are no quotes on the order book even though executable orders exist on both
sides of the market, the opening is automatically delayed. Trading in the affected securities will
be postponed. The Exchange specifies the length of the delay (Stop Trading Duration) in advance.
The Exchange may intervene in continuous trading by halting trading in a security for a specified
period of time. This can happen for different reasons.
The Exchange will not open trading in a given security as long as long as the auction
procedure does not result in the execution of all unlimited orders on the book (Non Opening).
In this status, it is also not possible to calculate a theoretical opening price (TOP).
The order book remains open and the opening procedure is restarted with each change in the
order book. The Non Opening condition lasts until all unlimited orders can be executed.
The Stop Trading condition depends on the probable next paid price for a security. If
this deviates by n% or more from the reference price, the Exchange halts trading in this security
for 5 or 15 minutes. The security will be revalued for reopening or go into Non Opening status.
Stop Trading "No Quote"
If there are no quotes in the order book even though executable orders exist on both
sides of the market, the Exchange imposes a Stop Trading condition for a predefined period of time
(Stop Time Duration).
Avalanche Stop Trading
The criteria for an Avalanche Stop Trading condition relate to a predefined period of time
(Avalanche Time) and a predefined price range (Stop Trading Range). If the next trade
during this period of time would potentially deviate from the reference price by an amount that is
higher than the predefined price range, the trade is not executed. The Exchange halts trading in the
security concerned for a predefined period of time (Stop Time Duration).
In extraordinary circumstances, the Exchange may also temporarily suspend trading
in a security. The duration of the suspension is decided on a case-by-case basis and should be
as short as possible. In the event of a suspension of trading, participants and the Exchange
must consider various aspects.
The issuer that submitted the original listing application for the security in
question may apply to the Exchange for a suspension in trading. Where possible, this should
take place at least 90 minutes before the opening of trading.
When assessing the imposition and duration of a suspension, the Exchange must weigh a number
of interests. The public interest lies in having an open, transparent market and continuous
pricing. On the other hand, there is the interest of ensuring that all participants are treated
equally with regard to price-sensitive information.
In the case of securities with a secondary listing and any related derivatives,
the Exchange also takes into account the decisions of the other major trading exchanges.
Moreover, in terms of equity securities with a secondary listing, the
Exchange also takes into account the decisions of the other major trading exchanges.