An Australian Federal Court has ruled that accounting giant PwC overused legal professional privilege when representing a tax client—a move that could deter clients from using multi-disciplinary practices and make their law-and-consulting offerings more difficult to manage, law firms say.

But the Big Four accounting firms see the judgment as a vindication of their business model because it held that a lawyer-client relationship exists in the context of multi-disciplinary practices (MDPs), affording clients the right to claim legal professional privilege over confidential communications.