The pending split at EY, one of the world's largest accounting firms and firmly among the Big Four, is proving to be a much more complicated move that's drawing out the timetable for negotiations, amid prickly internal discussions on finding the best deal for partners worldwide.

The move, which would hive off consulting from audit work amid major regulatory concerns across the globe of conflict of interest issues, is built on the firm's belief that the consulting arm would grow quickly. EY's internal documents cite the case of Accenture, but that firm's split from Arthur Andersen took place over 20 years ago, and the market is now altogether more crowded, The Wall Street Journal reported.