The post-Enron disintegration of Arthur Andersen in 2002 reduced the number of international accounting firms that audit nearly all of the world's largest public companies to the surviving Big Four — Deloitte, EY, KPMG and PwC. Despite market dominance, double-digit annual growth and annual global revenue above $120 billion in 2014 - the viability of the Big Four and their business model faces serious threats:- Widespread dissatisfaction with the standard form and language of their core product — the traditional "pass-fail" auditor's report. - The persistent "expectations gap" between their perceived performance quality and the stated desires of information users.- And especially, the questionable ability of the Big Four and their partners to survive a "black swan" financial shock - a litigation judgment or law enforcement sanction on the scale that destroyed Arthur Andersen. Count Down looks at the complex challenges facing the Big Four, questions the feasibility and achievability of the various proffered "solutions", and proposes an evolved model for Big Audit that would be both sustainable for the large firms and fit to serve the capital markets of the 21st century.