The S&P/ASX 200 is Australia’s principal institutional equity benchmark, tracking 200 of the largest and most liquid eligible stocks listed on the Australian Securities Exchange by float-adjusted market capitalisation. It is weighted heavily towards the biggest companies: as of 31 August 2026, its ten largest constituents accounted for 48.8% of the index.
The companies themselves range from Australia’s largest banks and miners to retailers, healthcare groups, technology businesses and real estate companies. The index also includes a number of overseas-domiciled businesses listed on the ASX, so the underlying audit market is not exclusively Australian.
Big4News examined the external auditor of every ASX 200 constituent, together with the first financial year of the current audit engagement where this could be established and the latest comparable audit fee identified.
The table below can be sorted by company, auditor, since and audit fee.
Data checked as of 30 September 2026. Audit fees are shown in Australian dollars.
ASX 200 Audit Market Share
The Big Four audit 93% of the ASX 200
Australia’s blue-chip audit market is highly concentrated.
EY has the largest number of ASX 200 audit mandates, auditing 55 companies, or 27.5% of the index.
PwC is close behind with 52 companies, or 26%, followed by KPMG with 46, or 23%. Deloitte audits 33 companies, or 16.5%.
Together, the Big Four audit 186 of the 200 ASX 200 constituents — 93% of the index.
That level of concentration is consistent with the broader structure of Australia’s listed-company audit market. ASIC reported in its 2022 audit-inspection findings that the six largest audit firms — the Big Four plus BDO and Grant Thornton — audited companies representing 95% of the market capitalisation of more than 2,100 ASX-listed entities.
That measure is not directly comparable with Big4News’ ASX 200 figures, which count individual company mandates rather than market capitalisation, but it illustrates how heavily large-company audit work is concentrated among the biggest firms.
Fourteen ASX 200 companies are audited by other firms
The remaining 14 companies, or 7% of the index, are audited by other firms
HLB Mann Judd: 4 audits
BDO: 3 audits
RSM: 2 audits
PKF: 2 audits
Grant Thornton: 1
Horizon Nexus (WA) Audit: 1
SW Audit: 1
The structure of the market is also receiving renewed policy attention. In June 2026, the Australian Treasury opened consultation on a package of possible reforms to the regulation of accounting, auditing and consulting firms. The options cover conflicts of interest, governance of large partnerships, eligibility standards for audit firms, audit surveillance and stronger enforcement. Treasury has framed the proposals partly around maintaining “confidence and dynamism in Australia’s audit market.”
See the KPMG Australia Scandal Timeline, which records how the KPMG audit-leaks scandal fed directly into the 1 July Treasury options paper.
Some of Australia’s largest companies have had the same audit firm for decades
Where an exact engagement start year could be established, the data reveals several exceptionally long audit relationships.
The most striking is ANZ, where KPMG has been the auditor since 1969. The company itself has publicly stated that relationship dates back more than half a century.
KPMG has also audited ResMed since 1994 and Insurance Australia Group since 2000. Deloitte has audited Auckland International Airport since 2000. PwC’s relationships with Fisher & Paykel Healthcare and Transurban date to 2001, while PwC has audited Computershare and Deloitte has audited JB Hi-Fi since 2002.
Australia does not impose a general requirement for listed companies to replace the audit firm after a fixed number of years. Instead, statutory rotation requirements focus on the individuals playing significant roles in an audit. ASIC explains that, generally, a lead or review auditor cannot play a significant role in the audit of the same listed entity for more than five successive financial years and must then have at least a two-year break.
Audit partners rotate, but the audit firm itself can remain in place for decades.
There has nevertheless been a cluster of recent auditor changes
Longstanding relationships coexist with more recent auditor turnover.
Among the 44 ASX 200 companies for which Big4News was able to establish an exact first financial year, 15 have a current auditor whose engagement began between FY2024 and FY2026. Because the start year remains unresolved for many other companies, this should not be interpreted as a rotation rate for the whole index.
Recent changes include PwC taking over AGL Energy for FY2026, EY at Charter Hall Group and IGO, PwC at Catalyst Metals and NexGen Energy, and KPMG at Westpac from FY2025. Deloitte’s first audit year at Telstra was FY2025, while KPMG began auditing Dexus in FY2025.
Other relatively recent changes include EY replacing the previous auditor at Super Retail Group for FY2024, KPMG taking over at Iluka Resources in FY2024 and Deloitte beginning its current CSL engagement in FY2024.
Macquarie has the largest audit fee identified in the dataset
A comparable audit-fee figure was identified for 147 of the 200 constituents.
Among those companies, the median identified fee is approximately A$1.75 million.
Macquarie Group has the largest figure in the dataset at A$53.0 million, paid to PwC for audit services across the group and controlled entities.
It is followed by Rio Tinto at approximately A$43.5 million, Westpac at A$29.2 million, News Corporation at A$26.1 million, Amcor at A$25.8 million, Block at A$22.6 million, ANZ at A$21.4 million and National Australia Bank at A$18.7 million.
For this analysis, Big4News has attempted to isolate fees for the audit or review of financial statements by the named auditor and its network. Tax, consulting, sustainability assurance, regulatory assurance and other non-audit services are excluded where the disclosure allows them to be separated.
Some ASX 200 constituents report their accounts and auditor remuneration in US dollars, New Zealand dollars or other currencies. Those amounts have been converted to Australian dollars only where an appropriate documented historical exchange rate was available.
The ASX 200 is not exclusively an Australian corporate universe
The presence of companies such as Alcoa, Amcor, Block, Newmont and Auckland International Airport highlights another feature of the index: eligibility is based on an appropriate ASX listing and the S&P/ASX methodology, not simply on Australian incorporation.
S&P Dow Jones Indices describes the benchmark as measuring the performance of the 200 largest and most liquid eligible stocks listed on the ASX by float-adjusted market capitalisation.
That has implications for the audit data. Some constituents are audited under US, New Zealand or other reporting frameworks, and some audit-fee disclosures originate in foreign currencies. The table standardises the auditor names and, where possible, converts the fees into Australian dollars to make the data easier to compare.
About the data
Auditor identifies the current external auditor of each ASX 200 constituent in the late-September 2026 dataset.
For the Big Four, member firms are grouped under the global network names Deloitte, EY, KPMG and PwC. Non-Big Four firms retain their individual names.
Since refers to the first financial year for which the current audit firm held the external audit engagement — not simply the year in which shareholders voted to appoint or reappoint the auditor.
Big4News was able to establish an exact first financial year for 44 of the 200 companies. The remaining fields are deliberately left blank. Historical evidence showing that a firm was already auditor by a certain date is not converted into an exact starting year unless the boundary of the current engagement can be established.
Audit fee is the latest comparable amount identified for the audit or review of the financial statements by the current audit firm and, where disclosed, other firms within the same global network.
A comparable figure was identified for 147 companies. The other 53 fields remain blank where the amount could not be isolated reliably, where a new auditor had not yet completed its first annual audit, or where a foreign-currency disclosure could not be converted on a sufficiently robust basis.
Non-audit, tax, regulatory assurance, sustainability assurance and other assurance work is excluded where the issuer provides enough information to separate those services.
Research was checked against company annual reports, independent auditor reports, ASX announcements, corporate-governance statements, SEC filings where applicable and other primary company documentation.
Data checked as of 30 September 2026.
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