Hans Pieterse prominent figure
More recent news is that Hans Pieterse left the building as well. Although Pieterse will still be on the payroll for a few months. Joop did not have a big profile (Quotenet is still searching for him on this image), but Hans Pieterse is well-known within the trading world.
Optiver replacing management
As someone already mentioned in the comments, the entire senior management has left the firm over the last years :
The silly thing is that Optiver’s kinda flushed their whole management in less than five years. Edwin van de Ven: gone. Randal Meijer: gone. Jelle Elzinga: gone. Hans Pieterse: gone. Joop van der Kruk: gone.
Johann Kaemingk still active in risk mangement
As far as I can tell founder Johann Kaemingk is still active in the risk management business of Optiver. His successor, CEO Paul Hilgers has taken over the helm beginning this year. One could wonder whether he could get along with Joop and Hans.
As a public speaker, Hans Pieterse is a lot easier to find.