The Chinese units of the global Big Four accounting firms Wednesday appealed a US judge’s ruling suspending them from auditing US-listed clients for six months, The Wall Street Journal reported. The Big Four are PricewaterhouseCoopers, Deloitte Touche Tohmatsu, KPMG and Ernst & Young. A Securities and Exchange Commission (SEC) administrative law judge last month suspended the firms over their refusal to hand over working papers about some of their Chinese audit clients. The appeal is the latest move in a battle over how much help US regulators can expect in investigating potential wrongdoing by China-based companies.