Key facts
Combined revenue of Deloitte, PwC, EY and KPMG — the four firms that audit nearly every company that matters.
Share of Britain's biggest audits held by the Big Four — a concentration no regulator has broken.
The detective question: who watches the watchmen, when the auditor is chosen — and paid — by the company it audits?
Every pension fund, every sovereign wealth fund, every savings account that touches a stock market runs on a single assumption: that somebody independent has checked the numbers.
Here is the detective question this investigation answers: who watches the watchmen of global capitalism? Because the auditor is chosen by the company it audits — and paid by it too.
This investigation maps the table: how much the four firms take in, how completely they own the market, how they got there, the disasters they signed off, and the efforts to break them up that never quite break anything.