The unlimited liability borne by auditors is “no longer tenable”, the European Commission said on Friday. It recommended that countries introduce legislation to limit the risks auditors face.

Regulators and policymakers have been concerned about concentration in the audit market since the collapse of Andersen in the wake of the Enron accounting scandal. That left only a “big four” of PwC, Deloitte, Ernst & Young and KPMG, who audit nearly all the world’s biggest companies and more than four-fifths of listed companies in Europe.