Welcome to the forums, Minnybae.
My limited understanding of the investment banking employment market is that there are indeed openings, but these tend to be more limited to the bottom end of the career ladder.
Something you may wish to consider - presuming not already done so - is to ask your bosses for advancement or an earnings increase directly. If you are that valuable to them, and you are considering moving firms, then this may highlight the importance of your role in the company, rather than allow it to be continued to be taken advantage of.
2c.