A volatility interruption is initiated if the potential auction price at the end of the call phase lies outside the dynamic and/or static price range. Volatility interruptions in an auction are indicated to the market participants.

A volatility interruption initiates a limited extension of the call phase, allowing market participants to enter new orders as well as to modify or delete orders in the order book. 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 (extended dynamic price range), the call will be extended until the volatility interruption is terminated manually according to FWB exchange rules.

In an opening auction this extended volatility interruption will be ended automatically once there is no longer an executable order book situation.

All non executed or partially executed market and limit orders are transferred to the next possible trading form according to their order sizes and trading restrictions.