ok let's split it into two portions, the bloomberg type, and financial institutions.

bloomberg type i'm not sure where is front and where is non-front. in certain way we can say it is quite a 'dead end job' because its specialized. they pay u well for the specialization and you continue to be in that job.. its difficult to move elsewhere because your experience is unique... sales jobs in bloomberg usually require a ex-banker/trader. because these are the ones that has to deal with other traders.

for financial institutions. if you are in an ibank, and doing back/middle office. its actually not so easy to move. back/middle office functions are important and to certain extent they are not paid to the level of their effort. if a person went into a middle office post, and did well, the boss would be more than happy to reward and keep him proportionally well. he wldn't want to let this guy move to the front office. and the front office bosses, even if they like you, unlikely they wld want to take you and deprive the middle office of a good talent. the front/middle/back functions have to be well linked to get the bank working.
so unless u are in a bank that postings are very supported, or u pick another bank to move to. else, the better one perform the harder it might be to move within a bank.