Large Public Company Auditor Market Share

We’re often asked about who audits who, and we frequently receive questions especially about the larger US public companies – in this case, identified as either Large Accelerated or Accelerated filers.

Over the summer, we posted an auditor market share analysis for the entire US public company market. One of the interesting trends we noticed was that the makeup of the auditor market changed drastically from the top of the market down, in terms of market capitalization. At the top, a relatively small handful of firms audited the vast majority of companies. At the bottom, the market exploded: no single auditor had more than a 5% share of the Smaller Reporting Company market.

Now, we turn to the larger US public companies. Who are the big players in that market? Of course everyone is familiar with the Big Four, and most people know the two other major global firms in Grant Thornton and BDO USA. In addition to these firms, the so-called Global Six, there are another 97 firms serving the total combined market of Large Accelerated and Accelerated Filers.

As you can see in the graphic below, however, the Global Six command about 89% of this market. Notably, Grant Thornton has just over 5% of the market, and BDO USA has just over 4%. Outside of the Global Six, 97 different firms split the remaining 11% of the market. But looked at another way, the Global Six have an even more commanding position in the US auditor market. Large Accelerated and Accelerated filers account for almost 97% of the total market capitalization of US public companies.

Click on the graphic below to expand.