Final answer:
A broker representing both the buyer and seller is known as an intermediary, similar to the role banks play in financial markets.
Step-by-step explanation:
A broker who represents both the buyer and seller in the same transaction operates as an intermediary. This term applies to a person or institution that acts as a middleman between two parties. In the context of financial capital markets, banks are a classic example of a financial intermediary, connecting savers who deposit funds and borrowers who take out loans. However, in real estate, such a broker might be referred to by different names depending on the local regulations, including dual agent or transaction broker. The two parties, much like the saver and borrower with a bank, may never directly meet but are both served by the broker's efforts to facilitate a transaction between them.