To ensure price continuity, continuous trading is interrupted by a volatility interruption whenever the potential next execution price of an order lies outside the dynamic and/or static price range around a reference price. Incoming orders are (partially) executed until the next potential execution price leaves the price corridor (exception: fill or kill orders). Market participants are made aware of this market situation.
A volatility interruption triggers a change of trading form: continuous trading is interrupted and an auction price determination is initiated, which is restricted to orders designated for continuous trading.

The volatility interruption consists of a call phase and price determination phase. After a minimum duration, the call phase in general ends randomly. However, if the potential execution price lies outside of a defined range, which is wider than the dynamic price range, the call will be extended until the volatility interruption is terminated manually according to FWB exchange rules.

Alternatively, the extended volatility interruption will be ended automatically once there is no longer an executable order book situation. If during the call phase of a volatility interruption or extended volatility interruption an intraday or closing auction is scheduled, the trading phase switches automatically to intraday or closing auction.