Sometimes, it just happens to be the opening position. If you interview at two firms, one hiring for analyst, the other for associate, you will just get the title of the job you get. I have seen many FE grads obtain associate positions straight out of the program. Keep in mind that the bank title is different from your position title. You may be an analyst and have a job title "junior trader" while another associate has a title of "quantitative analyst".
And if you have relevant experience, you will start with at least the same position as your previous job. It's part of the negotiation process.