The fiduciary details must be established and confirmed via a entrance agreement and a closing agreement. If the Law Firm had continued to advise the tax shelter business ( Monarch) of if the company being terminated concluded that relationship. So the law firm says close and they do then the law firm finds out it made a mistake. So is the law firm required to take the damage for the bad advice? Well probably not since you are nor required to place your self in harms way, even if it is fair play. So the law firm stuck with this contingent liability allows the attorney that provided the bad information to establish a firm replicating the same business the damaged client had. So the law firm not being required to place itself in harms way did not participate directly in the ceasing of opportunity presented by their bad advice but rather acted as attorney to the new firm. The damaged corporation now has to sue the law firm for bad advise and sue the attorney personally and his corporate entity. If it where the US this could be considered work product by Monarch and potentially a copyrighted activity that could assert the rights based on the value the attorney robbed.