That's the big four accounting firms. They're referring to the big four consultancy firms (which arguably isn't just four, and EY happens to be in). Also, Accenture was the consulting division of Arthur Andersen (which is involved in the Enron scandal).
The big 4 accounting firms are also the big 4 consulting firms. Deloitte, PwC, EY, and KPMG all have both large accounting arms as well as massive consulting arms.
There's also the "Big 3" or "MBB" which refers to the big 3 prestigious strategy consulting firms, Mckinsey, Bain, and BCG.
And then on the other end of the spectrum there's "WITCH" which is the consulting firms generally known as "body shops" that hire for quantity over quality. That's companies like Wipro, Infosys, TCS, Cognizant.
Accenture usually isn't included in any of the acronyms, it's just kinda an outlier despite how big it is. It's very much the same as how technically Microsoft isn't part of "FAANG", but whenever someone does say "FAANG" they typically just mean "the big tech companies" and you subconsciously think of MS as included in that.
I always hated that acronym, mainly because it classifies Netflix under the same umbrella as Microsoft (while I'll acknowledge that they're tech-savvy, Netflix has been (and still is) mainly a media company).
yes - Big 4 Auditors. For some reason, people also use Big 4 to refer to big technical implementation/System Integration consulting shops too, even though there are clearly more than four: Deloitte, EY, KPMG, Accenture, IBM, etc. Cognizant and Capgemini are creeping up there too
