Société Générale’s dented reputation took a further battering on Monday as French investigators claimed that the Eurex derivatives exchange raised the alarm last year over trading by Jérôme Kerviel, the man accused of masterminding banking’s biggest rogue trading scandal.

The news makes the positions of Daniel Bouton, SocGen chairman, and Jean-Pierre Mustier, head of corporate and investment banking, look increasingly shaky. A board meeting on Wednesday could decide their fates.