These are the same but then they are also not. Solvac EURONEXT:SOLV is a mono-holding, it owns 30% of $SOLB EURONEXT:SOLB
So I imagined they would both go up and down the same amount.
However, they don't.
Interesting.
I imagine the reason for this is that SOLVAC is owned mostly by the family that used to fully own Solvay chemicals.
fu