Big Four reports draw scrutiny over alleged AI hallucinations

The Big Four are facing renewed scrutiny over the use of generative AI in consulting thought leadership, after PwC joined KPMG, Deloitte and EY in being accused of publishing reports with hallucinated citations or unsupported claims. The controversy cuts into a core marketing channel for consultancies, which have long used whitepapers and surveys to showcase expertise and generate client leads.

Deloitte previously agreed to repay AU$440,000 ($291,245) to Australia’s Department of Employment and Workplace Relations after admitting generative AI was used in a report containing fake citations, phantom footnotes and a fabricated quote. GPTZero later claimed KPMG’s October 2025 report included 40 of the 45 sources hallucinated by generative tools, while an EY Canada cyber-security report was alleged to be 72% AI-generated and to include 16 of 27 citations that were broken or nonexistent.

PwC is now under pressure after GPTZero reviewed four studies published between 2024 and 2026 for clients in the Middle East and said there was an 84% chance that ‘Transforming Governance’ was entirely generative text. GPTZero said it found no public evidence for claims that PwC’s ‘Citizen Pulse’ framework was being used by governments in Denmark, Saudi Arabia, the United States and Australia. PwC said it takes accuracy seriously and is updating a limited number of supporting citations.