Having spent most of my career in upper management but not in banking, this is usually BS. I don;t know why it is in corporate america, but lying to employees is a disease and everybody does it.
In my posituion I never agreed to anything as a new hire without a letter guaranteeing it, and usually asigning bonus too. Without this, nobody wil keep tyheir word.
I cant tel you how manypeople haev been told something similar to you and it never happened or happened years later.
First off, great job for acing the exam, but the next thing is to ask yourself why they owuld promote you after only beig wiht them for 2 weeks. This is just simple pragmartism and common sense. There has to be someone else if not many who have doe the same and worked for them longer. This is just a safe assumption, but doesn;t mean they wont proote you.
The near future gets forgotten fast and often the person who says this is replaced too and the next guy wont honor what you tell him or her that the other supervisor said.
Justy do yur job dilligently and be bulletproof in everything. You should still be on probatuion foir at least 90 days or longer and that is what many think is th near future.
I guarantee you that 6 - 12 months wil go by and this person won;t recall because they are so used to playing with wiords that this has little meaning.