This inherent dual capacity, common to most professional services, naturally gives rise to conflicts of interest in cases where the professional acting as an agent, prescribes actions which he knows are to his own benefit as principal, rather than to the customers. There is nothing special about financial services in this respect.
Agency theory (principal-agent relationship) offers a valuable lens for assessing, inter alia, conflicts of interests. Financial services come jointly under the category of “experience goods” and “credence goods”; wherein, information is obtained by the consumers only during / after the services have been purchased or, perhaps, may not be able to obtain the same even after purchasing.