Spain’s IBEX 35 brings together international banks, electricity groups, infrastructure businesses and some of the country’s best-known consumer brands. Its audit market is concentrated entirely in four networks, with only one appointment separating the leader from its two closest competitors.
This table uses the September 2026 roster and identifies each company’s current financial-statement auditor, the first financial year audited by that firm and its latest disclosed audit fee. Fees appear in euros. It can be sorted by company, sector, auditor, since and audit fee.
Notes explain changes of auditor, broader fee categories, reporting periods and other exceptions.
A narrow lead for KPMG
KPMG holds 11 appointments, or 31.4% of the total. EY and PwC each hold 10, or 28.6%, while Deloitte holds four, or 11.4%. All 35 companies appoint a Big Four firm, and each is counted once in the appointment chart.
KPMG’s position is particularly visible in utilities. It audits four of the sector’s seven companies: ACCIONA Energía, Endesa, Iberdrola and Naturgy. EY audits Redeia and Solaria, while Deloitte audits Enagás.
The six banks divide differently. PwC audits Santander, CaixaBank and Bankinter; KPMG audits Sabadell and Unicaja; and EY audits BBVA. Mapfre, the seventh company classified as a financial business in the table, appoints KPMG.
The other firms’ portfolios reach well beyond banking and utilities. EY’s clients include Inditex, Amadeus, ArcelorMittal and Cellnex. PwC audits Telefónica, Repsol and Ferrovial. Deloitte’s four engagements are ACS, Enagás, Grifols and Inmobiliaria Colonial.
Recent changes alongside established engagements
Eight companies have a recorded first financial year with their current auditor of 2024 or later. Grifols’ Deloitte engagement, Merlin Properties’ PwC engagement and Unicaja’s KPMG engagement began in FY2024. EY began auditing Cellnex in FY2025, alongside Deloitte at Colonial and PwC at Ferrovial.
Two further changes take effect for FY2026. Deloitte succeeds EY at Enagás, while PwC succeeds Deloitte at Indra. Their fee entries therefore describe the outgoing firms’ completed FY2025 work and identify the recipients in the Notes column.
Longer relationships remain prominent. KPMG’s Mapfre engagement and EY’s Solaria engagement date from FY2015. PwC’s engagements at Santander and Bankinter, and EY’s at Fluidra, date from FY2016. Seven companies have recorded start years of FY2017.
“Since” refers to the first financial year audited by the current firm. The year in which shareholders approved an appointment can be earlier. Puig’s date follows the disclosed continuous individual-company audit tenure rather than its IPO date.
Santander dominates the recorded fee total
The fee figures in the table total approximately €335.1m, with a median of €3.3m. This is the sum of the recorded disclosures, including labelled predecessor fees and broader audit categories.
Santander’s €118.5m disclosure accounts for 35.4% of that total. BBVA follows at €26.7m, ArcelorMittal at approximately €24.8m, Iberdrola at €23.55m and Telefónica at €20.59m. Together, these five companies account for 63.9% of the recorded total. At the other end of the table, Solaria records €274,000 and Rovi €361,000.
The disclosures do not all measure the same scope of work. Santander’s audit category includes interim reviews, integrated financial-statement and internal-control audits, and regulatory reports. Enagás’ predecessor fee also includes review and internal-control work. Grifols reports its group audit fee rounded to the nearest €1m and includes interim limited reviews and PCAOB financial-statement audits.
Where companies separately identify audit-related services, sustainability assurance, tax or other work, those amounts are excluded. The notes also identify subsidiary fees paid to another network: Aena’s €553,000 KPMG figure excludes €380,000 paid to Grant Thornton for Luton subsidiary audits.
These differences limit direct price comparisons. The appointment chart measures current mandates; the table provides the latest disclosed fee information with its scope and timing explained.
Sources and methodology
The September 2026 worksheet was updated on 9 October 2026, with targeted checks against consolidated accounts, audit committee reports and issuer appointment announcements. Unchanged fields retain the supporting research from the earlier verified worksheet.
Fees generally relate to FY2025. Logista’s year ended on 30 September 2025 and Inditex’s on 31 January 2026. ArcelorMittal’s US$29.1m was converted to euros using the ECB’s 31 December 2025 reference rate, EUR1 = US$1.1750.
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