Insights · Governance & Risk

When trusted firms ship AI hallucinations

By AskLedger · 6 min read · Updated July 2026

In the space of a single year, KPMG, Deloitte and EY each had to pull or refund a report after someone discovered its citations were fabricated by AI. Not a rushed intern's memo. The flagship, paid deliverable of firms whose entire product is being trusted.

The reflex response is "they should have used better AI" or "they should have checked their work." Both miss what actually broke. These were not failures of model quality. They were failures of accountability: the AI produced confident claims with no durable link to a real source, and nobody inside the firm could tell what was real until an outside investigator checked, after publication.

A pattern, not an accident

Four of the most trusted names in professional services, plus a top law firm, in twelve months:

KPMG: 40 of 45 citations fabricated

KPMG pulled its October 2025 flagship report "Redefining excellence in the age of agentic AI" after the detection firm GPTZero found that only five of its 45 citations pointed to real sources. UBS, the UK's NHS, Swiss Federal Railways and Transport for London all said the report's claims about their AI usage were untrue or misleading.

The Register · TechCrunch · GPTZero · OECD.AI

Deloitte (Australia): a refunded government report

A $290,000 report for the Australian government contained references to non-existent academic papers and a fabricated quote from a federal court judgment. The corrected version disclosed, for the first time, that an Azure OpenAI GPT-4o tool chain had been used. Deloitte refunded the government.

Fortune · CFO Dive

Deloitte (Canada): a second country, a bigger report

A provincial healthcare report costing roughly $1.6 million was found to contain AI-generated false citations, including real researchers credited on papers they never wrote. The second such allegation against the firm in a year.

Fortune

EY (Canada): a citation to a report that doesn't exist

In May 2026, EY withdrew a report after an investigation found hallucinated citations, made-up data and footnotes, and a reference to a McKinsey report that does not exist.

Lawyer Monthly · Computing

Sullivan & Cromwell: an apology to the court

The law firm apologized to a New York court after an AI-assisted filing contained inaccurate citations and misquoted parts of the U.S. Bankruptcy Code. Same failure mode, higher stakes.

GPTZero's CEO warned that error-riddled papers from trusted firms "poison the well of information" and breed second-hand hallucinations, fabrications laundered into the next generation of research. When the source of trust becomes the source of error, the damage compounds.

Why "use better AI" misses the point

Hallucination is not a bug that a better model quietly retires. It is a property of how these systems work: they produce fluent, plausible text whether or not the underlying claim is real. You cannot make a model stop being confidently wrong.

What you can control is whether anything ships that the AI cannot prove. In every case above, the missing thing was the same: no evidence trail binding each claim to the source it supposedly came from. The output floated free of its provenance, so a fabricated citation looked exactly like a real one until a human, or an outside firm, checked each one by hand.

You cannot stop a model from being confidently wrong. You can refuse to ship anything it cannot prove.

The layer that was missing

This is the gap AskLedger is built to close. Not by making the model smarter, but by making its output accountable. Three things turn a floating claim into a provable one:

Captured at the moment the output is produced, the receipt looks like this:

event_type report.claim
output_hash 7f21…9c04 (the statement / citation produced)
evidence_refs [{ hash: 3b9d…, uri: "source-42.pdf", status: "verified" }]
verification citation_exists=true · quote_match=true
ai_model report-model-v5 · 2026-06-02
approved_by j.rivera · 2026-06-03T14:22Z
signature Ed25519 · valid

Now a fabricated citation is catchable at the gate: a claim whose evidence reference points to nothing, or fails its check, does not get a clean receipt, and does not ship. And months later, when a journalist or a client asks, you can show exactly what every claim was based on, verifiable by anyone with a public key.

To be clear about what this does and does not do. AskLedger will not stop a model from hallucinating. It makes the output accountable: every claim tied to a source, every check recorded, a human signature on the record, and nothing shipped that cannot be traced. The failures above were not "the AI was wrong." They were "no one could tell until it was public."

Trust you can hand someone

The firms that keep their credibility through this era will not be the ones that stopped using AI. They will be the ones that can show where every claim came from, before it goes out the door. On a consulting report, an audit, a regulatory filing, or a board deck, trust is no longer something you assert on your letterhead. It is something you can hand someone and let them verify for themselves.

Make every AI claim provable before it ships

AskLedger produces a signed, verifiable receipt for every AI output, binding it to the sources it used, the checks that ran, and the human who approved it. Open specification, Apache-2.0, verifiable by anyone with a public key.

This article summarizes publicly reported incidents, linked to their sources, and is general information, not legal or audit advice. Claims about specific firms reflect the cited reporting.