Due to price fluctuations, the effective weightings of the fund units can deviate from the specified target weightings of the investment strategy. If the weighting of a fund deviates from the target weighting by more than one percentage point, your entire portfolio will be rebalanced. Investments are sold and bought to restore the target weightings of the individual index funds.
This process is called rebalancing. It is carried out monthly on the first banking day of the month. There are no transaction fees involved.