You should see what KPMG signed off for GE 15 years or so ago

Click any of the links within https://money.cnn.com/2018/04/24/investing/ge-annual-meeting...

I wonder if PWC missed it by design, but then again I've been pessimistic about stuff like this after reading Lights Out, the book on the GE failure.

Auditors almost never find any fraud, and the SEC only rarely detects it on its own. Almost all cases of investor deception are revealed by short-sellers or insiders.

Ironically, it was PWC that came in after Deloitte and reported accounting irregularities to the board of Royal Ahold back in 2003 that lead to one of Europe's largest accounting scandals: https://www.sec.gov/news/press/2004-144.htm

KPMG was the auditors of USF before they were bought by Ahold, and their service period spans the window of when the accounting issues existed, so you have KPMG and Deloitte finally called out by PWC but that was almost 20 years ago.

Speaking as a former employee of a Fortune 100 company for who PWC provides services, PWC is pretty thoroughly "captured" by their clients... they will never report things like Sarbanes-Oxley issues even if they're hit over the head with them... because they're quite used to not finding any problems at this point.