The core difference: one lender vs. the whole market
When you walk into your bank, the advisor across the desk can only offer you that bank's mortgage. If their rate isn't competitive, or their rules don't fit your situation, that's the end of the conversation — you'd have to start over at the next bank, with another application and another credit consideration.
A mortgage broker flips that model. With a single application, a broker shops your file across dozens of lenders — the big banks, plus monoline lenders (wholesale lenders that only work through brokers and are often the rate leaders), credit unions, and alternative or private lenders for tougher files. You see the best fit, not just one option. That competitive tension is the structural reason brokers so often beat a single bank's offer.
