An auditor's responsibility is a professional responsibility. That is, a general liability for negligence, which is to some extent objectified through the rich practice, as well as "rules" for good auditing practice. The care and professional skill that can reasonably be demanded of practitioners of the profession in question must be exercised. Giving advice on matters that one has not sufficiently investigated is basically a culpable act.
Whether the advice was given orally or in writing is irrelevant. However, it creates evidentiary challenges if the advice was given only orally.
The assessment of whether deficient advice has been provided is influenced by the nature of the assignment the advisor has received. If the client wishes to operate in “grey areas”, the client must also accept that the outcome may not be as desired. The most obvious example of this is tax considerations, where the tax authorities impose a tax liability or disregard a transaction, and the client therefore does not achieve the position that the person concerned had hoped for. In this case, one must be reluctant to establish liability for damages for the advisor. At least when the transaction is solely for tax reasons and does not otherwise have the character of a normal business transaction, cf. U 1997.842 H.
In this context, it is also important what fee was paid for the advice. If you have only paid a modest fee, you can expect a lower quality of advice, which must still be correct.
Liability for damages in a contract is normally a liability with a reversed burden of proof, cf. for example the principle in Section 23 of the Danish Sales Act. It is therefore the person who caused the damage who must prove that he is not responsible for the damage. However, the rule of reversed burden of proof is not absolute, and for advisory liability the burden of proof generally lies with the injured party.
Typically, we will have a professional association issue a response in order to determine whether the act was liable. Failure to obtain such a response may be considered procedurally damaging, cf. U 2004.1153 V. It is also up to the client to demonstrate – or at least make it probable – the loss he or she has suffered as a result of the advice giving rise to liability.
Whereas it is the client's responsibility to provide proof of fault and loss, it is the advisor's responsibility to provide proof of the circumstances that he is most likely to be able to (counter)prove.
The injured party cannot demand that the tortfeasor or his insurance company calculate any loss. The injured party must obtain assessments themselves that can document a loss, and prove that the loss is not due to circumstances other than the advice (e.g. pollution on neighboring land, or lack of business potential for the acquired property).
Guilt: Incorrect advice is liable = culpable
The burden of proof: The injured party must prove that the advice was part of the instruction, that it was incorrect (e.g. through a response) and the injured party must be able to document the loss themselves, as well as the causal link.
Compensation: A disappointed expectation of the advice does not generally trigger any compensation, cf. U.1996.200/2H.