Your theory, Nachum?
At this point? There are only wild speculations. We only know that that a lot of bankers are dead in a relatively short period of time.
I could only state the obvious, which is that these people are liabilities that needed to be shut up. Also, some of the murders included family members, wives and children. That suggests that it is some sort of punishment as well. It is vindictive.
Now who has a motive to shut up a lot of bankers in mid-level positions, angry enough to kill family with them and wants to do it all in a short period of time?
Possible answers:
*Someone who is planning to do something on a large scale soon.
*Someone who has already done something and wants to cover it up.
*Someone with international interests.
*Someone who is completely ruthless.