Final answer:
John Jones, as an agent to X Co., breached his fiduciary duty by not listing the property at the instructed price and instead making a private deal, thus violating principles of agency law.
Step-by-step explanation:
The legal issues raised in the scenario pertain to agency law, particularly the duties of an agent to their principal. In the given situation, X Co. has hired John Jones as an agent to sell its property. By agency law, John owes a fiduciary duty to X Co., which includes duties of loyalty and obedience. By not listing the property at the instructed price of $1 million, and instead selling it directly to Mary for $900,000, John has breached these duties. He acted contrary to his principal's instructions and potentially deprived the principal of receiving a higher offer. Although he succeeded in selling the property at the authorized minimum price, John's failure to follow X Co.'s instructions and his decision to make a private deal with Mary raise significant issues regarding his conduct as an agent.