This chapter explores potential threats to the survival of the Big Four. The options for splitting and the attendant difficulties are examined. There has been some discussion between the CMA, FRC and the ICAEW and this intervention has probably postponed any decision for the moment. There are merits to splitting the Big Four, especially an audit-only split from consultancy work, which would provide greater freedom of choice and a slightly greater degree of independence in the audit market. Alternatively, developing the mid-tier firms of BDO and GT to create a Big Six is examined together with ways in which this might be achieved. Finally, we built a model for simulating alternatives to evaluate the degree of freedom in the audit market. That modelling process shows the audit-only split does provide a much greater degree of freedom of choice. The final axiom concerns independence and audit quality and states: higher quality audits are achieved with greater independence.