Where there is smoke, there is fire. The stock of listed prop trader has steadily declining since Nov 8 and nobody really knew why. There's always a reason though and this could be one of them.
The Dutch Central Bank had a policy in place that had Dutch proprietary trading firms treated as 'local firms'. This meant that the capital requirements were easier and the bonus cap that the Netherlands has for banks (max 20% of salary) would not apply.
Now the DNB sent a letter stating that they are forced by the the EBA (European Banking Authority) to stop that special treatment as of March 2018. More info can be found here.
This is pretty bad, not just for Flow, who has stated it already conservatively financed anyway but for the industry as a whole.
Prop trading has been a Dutch success story and it seemed very likely that trading firms had Amsterdam as their number 1 location after Brexit. The bonus cap thing may disturb those plans.
The DNB press release can be found here. Media reported that interest organisations are internally discussing next steps and the further talks will be held with the regulator.