Have any philosophers written about ethics and the financial services industry?
I'm less interested in the bits covered by law (insider trading, etc) than ethical issues around the role the industry and its members play in society.
Topics relating to morally permissible behaviors of corporations are dealt in the field of business ethics. Finance ethics is a branch in the field. Due to the complexities as it relates to other fields (e.g., laws and accounting), finance ethics has not caught the wild imaginations of philosophers yet, as its paucity in business ethics entry in Stanford Encyclopedia of Philosophy testifies. I find the entry in Wikipedia to be far more helpful regarding finance ethics.