It heavily depends upon the job that you are applying for - "investment banking" is everything and nothing.

From my personal experience (I worked as a derivatives trader for some years): I mostly asked technical and very detailed questions about the position that the candidates were applying for. The reason is, that I wanted to figure out if a candidate was really passionate about this area and did some self study. I had the impression that many people were just applying because they thought that it was a "cool" job or because they heard it was well paid.

To answer your question: make sure you know all the basics in the area you want to work in and are able to demonstrate some advanced knowledge. I.e. you mustn't interview with a trading desk and not know Hull's book back and forth.

Of course, there will be additional general logic questions and the usual "soft" questions but especially for very technical positions, it is a deal breaker if you can't demonstrate that you master the foundations.