According to DeMorgan.be, one of the names on the shortlist was Symmon or a variant like Symon or Symona, to give the bank a more personalized flavor. A human name like Symmon would push the idea that the bank is simple to use, has good service and is reliable.
But there were two objections to that name.
One is that it was not particularly Belgian, which many desired.
The other was that the name Symmon was too - Jewish!
Although market analysis showed that the resistance of the Muslim community [to the name] is not insurmountable, the Dexia marketers saw the connotation as a major limitation.
In the end, they chose the name Belfius.
Jewish newspaper Joods Actueel tried to contact Belfius and the advertising agency that helped choose the name, but they refused to comment on that aspect of the story.
The paper noted that Simon is a common Flemish name, among the top twenty names given to babies in Belgium.
It is not clear whether the public relations firm pro-actively polled the name and found Muslim objections to it, or if it assumed that there would be objections from Muslims and that this was an obstacle that needed to be overcome.
The story shows that either the Muslim community in Belgium is inherently anti-semitic, or it is assumed to be so by the Belgian public. Or, more likely, both.