In most situations this is called insider trading and is considered unfair in public markets since the trades of insiders may be concealed, like through a family member.

Within an organization making a decision that advantages oneself is unethical since the purpose of the most organizations is not to fulfill the personal interests of its employees.

It would make some sense to convert all property holdings of a government employee to financial instruments related to the health of the government such as treasury notes. That way their personal interests are at least aligned with those of the government. To the degree that the instruments measure aspects of the government that are not totally aligned with the governed is a problem however.