This is a living resource and will be updated as new scandals emerge and existing cases develop.
Originally published on: 26 September 2026
The Big Four audit firms — Deloitte, PwC, EY and KPMG — occupy a uniquely influential position in global business. They audit many of the world’s largest companies, advise governments and corporations, and employ hundreds of thousands of professionals across international networks.
But their history has also been punctuated by major audit failures, corporate collapses, regulatory investigations, conflicts of interest, confidentiality breaches, whistleblower allegations and other controversies.
This timeline brings those episodes together in one place.
Each scandal appears once, dated to the point at which it first became publicly significant — whether through a corporate collapse, regulatory announcement, court action, parliamentary disclosure or major public revelation. Later developments, including investigations, sanctions, settlements and leadership changes, are incorporated into the original entry rather than treated as separate scandals.
Where Big4News has created a dedicated timeline, readers can follow the link for the complete chronology and underlying sources.
2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 |
2026
24 March 2026 — KPMG Australia audit-leaks scandal
KPMG | Australia
A long-running internal dispute at KPMG Australia burst into public view when Australian senator Deborah O’Neill disclosed allegations from a former KPMG employee under parliamentary privilege. The whistleblower alleged that confidential client information had been improperly shared within the firm and used in attempts to win major audit mandates.
The allegations centred initially on confidential Lendlease material relating to rival audit bids. What followed developed into a much broader crisis involving further confidentiality breaches, scrutiny of KPMG’s treatment of the whistleblower, the resignation of senior leaders, lost client work, regulatory and parliamentary investigations, and restrictions on the firm’s ability to bid for new government work.
KPMG subsequently acknowledged that its initial investigation of the whistleblower’s allegations had not been conducted with the necessary rigor and apologized to the whistleblower and affected clients.
See the full KPMG Australia scandal timeline →
30 June 2026 — EY staff accused of accessing Australian prime minister’s banking information
EY | Australia
Two EY employees were dismissed after allegedly accessing Australian prime minister Anthony Albanese’s private banking information while working on secondment at Commonwealth Bank. One EY employee was charged by police with unauthorized access to restricted data; another man with no connection to EY was also charged. EY said the employees had been dismissed.
2025
August 2025 — WHSmith accounting scandal
PwC | United Kingdom
WHSmith disclosed that profits in its North American business had been overstated by around £30 million, largely because supplier income had been recognized too early. The revelation prompted a sharp reduction in the retailer’s profit forecast and triggered a dramatic fall in its share price. WHSmith commissioned Deloitte to conduct an independent review, and CEO Carl Cowling later resigned.
PwC had audited WHSmith since 2015. In June 2026, the UK Financial Reporting Council opened a formal investigation into PwC’s audit of the company’s financial statements for the year ended 31 August 2024. The FRC stressed that opening an investigation does not constitute a finding that PwC breached auditing requirements.
21 July 2025 — EY whistleblower lawsuit
EY | United States
Former EY partner Joe Howie filed a federal lawsuit alleging that EY retaliated against him after he repeatedly raised concerns about audit failures, securities-law violations and improper professional conduct involving several clients. His complaint alleged that EY stripped him of leadership roles, threatened early retirement and ultimately removed him from the partnership because of his whistleblowing activities. EY has contested the case, and the allegations have not been adjudicated.
25 June 2025 — Netherlands Big Four exam-cheating scandal
Deloitte, PwC and EY | Netherlands
The PCAOB fined the Dutch member firms of Deloitte, PwC and EY a combined $8.5 million after finding widespread improper answer-sharing on mandatory internal training tests. Hundreds of personnel were involved, including partners and senior leaders, over a period lasting at least from 2018 through 2022. Deloitte and PwC were each fined $3 million and EY $2.5 million. The Dutch regulator placed the firms under intensified supervision.
16 April 2025 — EY drawn into the Post Office Horizon scandal
EY | United Kingdom
The UK Financial Reporting Council announced an investigation into EY’s audits of the Post Office, specifically examining audit work connected with the Horizon IT system. EY had audited the Post Office during years in which accounting discrepancies generated by Horizon contributed to the wrongful prosecution of hundreds of sub-postmasters. The opening of the investigation does not constitute a finding that EY breached auditing requirements.
2024
13 September 2024 — PwC China / Evergrande audit scandal
PwC | China
Chinese regulators imposed RMB441 million (about US$62 million) in penalties on PwC Zhong Tian and suspended its business activities for six months over its audits of Evergrande’s mainland subsidiary Hengda. The China Securities Regulatory Commission said PwC failed to detect significant financial fraud, while PwC itself said the audit work had fallen “unacceptably below” its standards. Six partners were terminated and five staff left or were dismissed, while PwC China’s territory senior partner stepped down from that role.
10 April 2024 — KPMG Netherlands exam-cheating scandal
KPMG | Netherlands
The PCAOB imposed a record $25 million penalty on KPMG Netherlands after finding widespread improper answer-sharing on mandatory internal training tests between 2017 and 2022. The regulator also found that the firm had made multiple misrepresentations about its knowledge of the misconduct. Former head of assurance Marc Hogeboom was permanently barred from association with a registered public accounting firm and fined $150,000.
2023
August 2023 — Deloitte / STARK Corporation
Deloitte | Thailand
Investors brought proceedings against Deloitte Touche Tohmatsu Jaiyos and an individual auditor over the audit of scandal-hit Thai company STARK Corporation. The underlying corporate scandal involved alleged falsification of financial statements and serious accounting irregularities. The Southern Bangkok Civil Court proceeding against Deloitte was filed in August 2023, with a later 2024 ruling allowing a class action to proceed. The allegations against Deloitte remain contested and are not findings of liability.
17 March 2023 — Deloitte / China Huarong audit scandal
Deloitte | China
China’s Ministry of Finance imposed penalties of approximately RMB212 million (US$31 million) on Deloitte and suspended its Beijing operation for three months over deficiencies in its audits of China Huarong Asset Management. The ministry found Deloitte had failed adequately to assess Huarong’s assets and business operations and had not properly addressed irregular transactions and other issues affecting the accuracy of Huarong’s financial reporting.
10 March 2023 — Silicon Valley Bank / Signature Bank audit scrutiny
KPMG | United States
KPMG came under intense scrutiny after the rapid failures of Silicon Valley Bank and Signature Bank, both of which it audited. KPMG had issued clean audit opinions shortly before the banks collapsed. The firm said its audit opinions reflected the evidence available at the dates they were issued and that subsequent market-driven events could not have been anticipated in those opinions.
Subsequent shareholder litigation alleged that KPMG had made misrepresentations in connection with Signature Bank’s financial reporting and risk disclosures; those allegations are contested and should not be presented as findings.
23 January 2023 — PwC Australia tax-leaks scandal
PwC | Australia
The scandal became public after Australia’s Tax Practitioners Board announced that former PwC tax partner Peter Collins had breached professional obligations by improperly sharing confidential government information obtained while advising Treasury on anti-tax-avoidance measures. The matter escalated dramatically in May 2023 when parliamentary disclosure of internal PwC emails showed that the confidential information had circulated far more widely inside the firm and had been used in work for multinational clients. Treasury subsequently referred the matter to the Australian Federal Police.
The fallout was extraordinary: CEO Tom Seymour resigned, eight partners left or were removed, government work dried up, and PwC sold its Australian government consulting business for A$1. The Australian government later described the episode explicitly as the “PwC tax leaks scandal” and launched a major package of regulatory reforms in response.
11 January 2023 — Americanas accounting scandal
PwC and KPMG | Brazil
Brazilian retailer Americanas disclosed material accounting inconsistencies on 11 January 2023, triggering a rapid corporate crisis that led to judicial reorganization days later. The company subsequently said documents reviewed by an independent committee indicated that its financial statements had been manipulated by former management.
Brazil’s securities regulator, the CVM, opened separate proceedings examining the work of PwC, which audited Americanas for 2019–2022, and KPMG, which had audited the company for 2017 and 2018. The investigations concerned possible irregularities in the firms’ audit work; they did not themselves constitute findings of wrongdoing by either auditor.
2022
July 2022 — KPMG Lower Gulf governance scandal
KPMG | United Arab Emirates / Oman
A governance crisis erupted publicly at KPMG Lower Gulf after partners raised concerns about the leadership of chief executive Nader Haffar, including allegations concerning conflicts of interest, the firm’s leadership-election process and the treatment of partners who had challenged management. KPMG Lower Gulf announced that it would rerun the CEO election and commission an independent external review of its governance.
28 June 2022 — EY US exam-cheating scandal
EY | United States
The US Securities and Exchange Commission imposed a $100 million penalty on Ernst & Young after finding that audit professionals had cheated on exams required to obtain and maintain CPA licences and on continuing professional education tests. The SEC also found that EY had withheld evidence of the misconduct from the regulator during its investigation. EY admitted the facts underlying the SEC’s charges and agreed to extensive remedial measures. At the time, the penalty was the largest the SEC had ever imposed on an audit firm.
2021
1 September 2021 — KPMG accused of misleading the UK audit regulator
KPMG | United Kingdom
The UK Financial Reporting Council brought a formal disciplinary complaint against KPMG and several current and former employees over allegedly false and misleading information and documents supplied during inspections of KPMG’s audits of Carillion and Regenersis. The complaint was distinct from the underlying Carillion audit investigation: it concerned KPMG’s conduct toward the regulator itself.
The case later produced serious findings. In 2022, an independent disciplinary tribunal found misconduct including dishonesty in some instances and lack of integrity in others. KPMG had self-reported the matters to the FRC and admitted responsibility for the acts of the individuals concerned, which the tribunal treated as significant mitigation.
2 August 2021 — EY US audit-independence scandal
EY | United States
The US Securities and Exchange Commission charged EY, one current partner and two former partners with violating auditor-independence rules during a competition to win a major public-company audit. The SEC found that EY personnel solicited and received confidential competitive intelligence and audit-committee information from the company’s chief accounting officer during the request-for-proposal process. EY agreed to pay a $10 million civil penalty and accept a censure and remedial undertakings; the individuals also received penalties and suspensions. The respondents settled without admitting or denying the SEC’s findings.
April 2021 — Babcock accounting and audit scandal
PwC | United Kingdom
Babcock International disclosed major accounting adjustments following a wide-ranging review of the profitability of its contracts and the carrying value of assets and liabilities. The review ultimately resulted in approximately £2 billion of adjustments, including prior-period accounting errors and substantial impairments. PwC had audited Babcock throughout the affected period.
The UK Financial Reporting Council subsequently investigated PwC’s audits. In 2023, PwC and two former audit partners admitted numerous serious breaches relating to the 2017 and 2018 audits, including repeated failures to challenge management and obtain sufficient audit evidence. Further sanctions followed in 2026 over the 2019 and 2020 audits, where PwC and the audit partner admitted serious and numerous breaches involving areas including contract accounting, financing arrangements, goodwill and asset capitalization.
2020
18 June 2020 — EY / Wirecard scandal
EY | Germany
German payments company Wirecard announced that EY had refused to sign off its 2019 accounts because the auditor could not confirm the existence of €1.9 billion in cash, around a quarter of the company’s reported balance sheet. Wirecard subsequently said the money probably did not exist and filed for insolvency on 25 June owing creditors almost €4 billion. EY had audited Wirecard for more than a decade.
The collapse triggered intense scrutiny of how the alleged fraud had remained undetected for years (despite whistleblower Pav Gill sending the firm a dossier highlighting fraudulent invoices and documentation). An independent KPMG investigation commissioned before the collapse had already reported that it could not verify significant parts of Wirecard’s third-party acquiring business because sufficient documentation had not been provided.
19 January 2020 — PwC / Luanda Leaks
PwC | Angola / Global
The International Consortium of Investigative Journalists published the Luanda Leaks, based on more than 715,000 documents concerning the business empire of Isabel dos Santos, daughter of Angola’s former president José Eduardo dos Santos. The investigation put PwC under intense scrutiny for the extensive accounting, audit and advisory work performed by firms in its international network for companies linked to dos Santos and her husband. ICIJ reported that PwC had continued providing services after a number of banks and other professional firms had become unwilling to work with her businesses. PwC subsequently said it had begun an investigation into its work and moved to terminate relationships with entities controlled by the family.
2019
17 December 2019 — NMC Health accounting scandal
EY | United Kingdom / UAE
The NMC Health scandal first became publicly significant when short seller Muddy Waters published a report on 17 December 2019 questioning NMC’s financial statements, balance sheet and debt disclosures. NMC’s shares fell sharply and the company launched an independent review within days.
The crisis intensified in 2020 when NMC disclosed more than $4 billion in previously undisclosed debt, entered administration and became the subject of regulatory investigations and major litigation. EY had audited NMC for years; the FRC opened an investigation into EY’s 2018 audit in April 2020. NMC’s administrators later accused EY of negligence, while EY denies wrongdoing and says it was itself deceived by a sophisticated fraud.
23 September 2019 — PwC US auditor-independence violations
PwC | United States
The US Securities and Exchange Commission charged PwC with auditor-independence violations and improper professional conduct relating to 19 engagements for 15 SEC-registered issuers. The SEC found that PwC had provided prohibited non-audit services to an audit client, including exercising decision-making authority in designing and implementing financial-reporting software, and had weaknesses in controls governing non-audit services. PwC agreed to pay more than $7.9 million in monetary relief and accepted remedial undertakings, without admitting or denying the findings.
23 September 2019 — Thomas Cook collapse and EY audit scrutiny
EY | United Kingdom
Thomas Cook collapsed after rescue negotiations failed, triggering immediate scrutiny of its financial reporting and EY’s audits. EY had taken over as auditor from PwC in 2017. On 1 October 2019, the UK Financial Reporting Council opened an investigation into EY’s audit of Thomas Cook’s 2018 financial statements, later extending it to the 2017 audit.
The significance of the episode became clearer later: in 2025 EY and the audit partner admitted serious breaches relating to goodwill impairment, going concern and independence, and the FRC said both audits failed in their principal objective of obtaining reasonable assurance that the financial statements were free from material misstatement. The FRC did not allege that amounts in the accounts were actually misstated or that use of the going-concern basis was inappropriate.
2018
April 2018 — KPMG / VBS Mutual Bank
KPMG | South Africa
KPMG South Africa came under renewed scrutiny over its audit of VBS Mutual Bank after two partners connected with the audit resigned while facing disciplinary charges over failures to disclose relevant financial interests. KPMG said one partner had provided misleading information concerning loans held with VBS and launched an independent investigation into the audit.
The bank’s curator subsequently withdrew VBS’s 2017 audited financial statements after concluding that they contained material misstatements and could no longer be relied upon. KPMG was the external auditor.
The affair deepened an already serious crisis at KPMG South Africa arising from its earlier Gupta and SARS controversies. KPMG itself later treated VBS as a distinct legacy issue, separate from the Gupta and SARS matters.
15 January 2018 — Carillion collapse
KPMG | United Kingdom
UK construction and outsourcing group Carillion entered compulsory liquidation on 15 January 2018, leaving major public contracts unfinished, thousands of jobs at risk and a large pension deficit. KPMG had audited Carillion since its creation in 1999 and had issued an unmodified audit opinion on its 2016 financial statements only months before the collapse. Parliament subsequently scrutinized all four Big Four firms for work performed for Carillion, while the FRC opened an investigation into KPMG’s audits for 2014–2016 and additional audit work performed in 2017.
The scandal eventually produced major findings against KPMG. In 2023 the FRC imposed sanctions following its investigations into the Carillion audits.
23 January 2018 — KPMG / PCAOB inspection-leaks scandal
KPMG | United States
US prosecutors charged former KPMG executives and former PCAOB employees in a scheme to steal confidential information identifying which KPMG audits would be inspected by the regulator. Prosecutors alleged that KPMG personnel used the information to improve the firm’s performance in PCAOB inspections. One former KPMG partner had already pleaded guilty earlier that month.
The affair later produced criminal convictions and a $50 million SEC penalty against KPMG in 2019.
About Claudine Cassar
I’m a corporate anthropologist and former Deloitte equity partner. I sold my technology business to Deloitte in 2016 and led the Malta Consulting team for five years. I am the founder and editor of Big4News, which provides independent, clear analysis of PwC, Deloitte, EY, and KPMG — free from corporate spin.
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