Using our CompanyIQ SEC research database, we analyzed the annual 10-K filings of R3000 and S&P 500 companies for 2020 to 2023 to provide an overview of auditor tenure, auditor changes, auditor market share, and audit fees.

A review of Russell 3000 and S&P 500 companies over the past four years indicate that they rarely change auditors.

Among our findings:

• 12 years is the median auditor tenure for the R3000.
• 23 years is the median auditor tenure for the S&P 500.
• 85% of R3000 companies did not change their auditor in the last four years.
• 97% of S&P 500 companies did not change their auditor in the last four years.
• A surprising number of companies report having the same auditor for 100 years or more, including one, Procter & Gamble, that has not changed since 1890.