Fridays(option expiration): Its not every month it goes down. Seems to correlate with the trend. When negative trend > it has cone only 10-20% down. So max down is -20% around expiration day (since 2-3 years). Exceptions below.
Looks like the 25kEUR level can be touched (in May, latest 11.June)
-> worse case 18kEUR (that is -40% from this moment)