What constitutes a breach of fiduciary responsibility between a buyer's broker and the buyer during negotiations?

A breach of fiduciary responsibility occurs when a broker fails to act in the best interests of their client, which is the buyer in this scenario. In this case, when the broker tells the seller about the buyer's plans to subdivide the property, they compromise the confidentiality and strategic advantage of their client. Such disclosure could potentially harm the buyer's negotiating position, as it reveals intentions that could lead the seller to adjust their strategy or pricing in response to that information.

This breach is significant because fiduciary duty mandates that the broker must keep the buyer's best interests at the forefront of all negotiations, maintaining confidentiality about sensitive information. The other options, such as disclosing the home's previous listing price or suggesting making the first offer, do not constitute breaches of fiduciary duty as they do not compromise the buyer’s position or confidentiality in negotiations to the same extent.