Typically, additions and removals from the index are made only as part of the regular adjustments. In exceptional cases, a so-called "fast entry" may occur. For example, if there is a major new public offering during the year, the stock may be added to the index ahead of schedule.
Conversely, if an index constituent experiences a dramatic deterioration in its business environment, the “fast exit” rule allows the security to be removed from the index relatively quickly.
Further information on this can be found in the current index rules of the Vienna Stock Exchange.
