You couldn't make this up - but
@EYnews and
#AI can!
[Credit
#PeritiAI for use of its AI tools to check the content and reports. But blame us for the post images. Clearly AI wouldn't create such amateur MS Paint images.]
As recently as 23 January 2026 EY was, like all the large professional services firms, virtuously preaching to mere mortals and, in fairness, internally about how the conglomerate's expertise and advice in AI will help their clients and their employees. So we better listen to them, right?
This quote is both priceless and prescient: "To truly advance responsible AI, we urge you to take concrete steps today. Begin by adopting the outlined mitigation framework to embed provenance and confidence thresholds into your workflows."
Jump forward not even a full 4 months and someone at EY didn't get that memo. We read on 15 May that "EY [Canada] has withdrawn a study on loyalty rewards programmes that included apparent
#AIhallucinations and fake footnotes, in the latest example of a professional services firm being led astray by the new technology."
The study was created [literally created 😅] to market its hashtag#cybersecurity business and used made-up data, mis-attributed citations and referenced a
@McKinsey report that does not exist as discovered by online researchers.
The study titled “Points of Attack: Uncovering Cyber Threats and Fraud in Loyalty Systems” was removed from its website after the hallucinations were reported by the research group
@GPTZeroAI late on Thursday 13 May 2026.
Now of course EY is the only bogeyman Big 4 out there seeking to scare firms into using their AI services. But they are, like Deloitte, one of the few who don't practice want they preach in this area. In 2025, Deloitte had to pay money back to the Australian government after using AI in $440,000 report. The Aussies received a partial refund after several errors were found in a report into a department’s compliance framework. This was 6 October 2025. Then in 22 December 2025 Deloitte warned us that "AI doesn’t lie, it hallucinates and M&A due diligence must address that". This Big 4 pronounced that "root causes of AI hallucinations often lie in biases within training data, algorithmic errors, misinformation in data sources, or limitations inherent in AI models. For instance, a 2024 medical study found that when large language models were asked to generate references for systematic reviews, GPT-4 hallucinated 28.6% of citations." Question. Why did it not cited its own failings just two months earlier.
Moral of the story is that if you are a Big 4 never air your dirty laundry while hawking your services to clean others. However it could be worse, at least none of the Big 4 have been caught cheating in ethics exams...wait a minute! 🫣🤔
All links to sources in comments - way too many for post character limitations.