Mortgage bankers are in the sole business of lending money.
Mortgage brokers are middlemen who, by state law, work on behalf of borrowers. Possibly, because mortgage brokers work with many different lenders. They may also have access to lenders that do not have an office in your state, but are licensed to lend money there. However, while mortgage brokers research many lending sources, it would be nearly impossible for them to access every single lender and every mortgage product, simply because there are thousands out there. Not necessarily, though the broker does perform a service for which he or she receives a fee.