Although all the facts are not known, it is perplexing how such a basic error involving billions of dollars could go undetected by the auditors.
The auditors failure to detect the error resulted in them all being fired. 
mnli hypothesis: The auditors failure to detect the error resulted in them all being fired.  premise: Although all the facts are not known, it is perplexing how such a basic error involving billions of dollars could go undetected by the auditors.