What are the best free sources for comparing public company audit firms and their assurance track records?

If you want to compare public-company audit firms and get a feel for their assurance track records, the best free sources are usually a mix of regulatory databases, inspection reports, enforcement actions, and company filings. None gives the whole picture, but together they work well.

Best free sources

1. PCAOB inspection reports

• What it gives you: The most direct public look at audit-firm quality for firms auditing U.S. public companies.
• Why it’s useful: Shows deficiencies the PCAOB found in selected audit engagements and in the firm’s quality control system.
• Best for: Comparing U.S. audit firms, especially the Big 4 and larger PCAOB-registered firms.
• Where: PCAOB website under inspection reports.

2. SEC EDGAR filings

• What it gives you: Public company annual reports and proxy statements, including:
  • auditor name
  • audit fees vs. non-audit fees
  • auditor changes
  • material weaknesses
  • restatements and going-concern language in some cases
• Why it’s useful: Lets you evaluate how often a firm shows up with companies that later restate or disclose internal-control issues.
• Best for: Client-level tracking and fee analysis.
• Where: SEC EDGAR.

3. SEC enforcement releases and litigation releases

• What it gives you: Audit-firm or partner sanctions, settlements, and misconduct cases.
• Why it’s useful: Helps identify firms with disciplinary history beyond routine inspection findings.
• Best for: Spotting serious track-record issues.
• Where: SEC website enforcement section.

4. PCAOB disciplinary orders and settled administrative actions

• What it gives you: Official sanctions against auditors, firms, and partners.
• Why it’s useful: More severe than inspection deficiencies; useful for risk signals.
• Best for: Public-company audit quality comparisons.
• Where: PCAOB website under disciplinary proceedings.

5. Company proxy statements (DEF 14A)

• What it gives you: Often includes audit committee discussion of auditor choice, fees, and sometimes reasons for auditor retention/change.
• Why it’s useful: Can reveal patterns like frequent auditor turnover, tender processes, or heightened audit committee concerns.
• Best for: Context around auditor tenure and changes.
• Where: SEC EDGAR.

6. Restatement databases and press releases

• What it gives you: Information on financial restatements and their causes.
• Why it’s useful: Restatements are not always the auditor’s fault, but repeated association can be a signal.
• Best for: Track-record screening.
• Free sources: Company press releases, SEC filings, and some academic/market sites with limited free access.

7. Audit Analytics / Capital IQ / similar

• What it gives you: Strong comparative data on audit firms, restatements, fees, and auditor tenure.
• Why it’s useful: Probably the best for structured comparisons.
• Caveat: These are generally not free, but worth mentioning because they’re the benchmark if you later need paid tools.

8. Annual reports and 10-Ks

• What it gives you: Auditor opinion, critical audit matters, internal control opinions, and fee disclosure.
• Why it’s useful: Good for reviewing a firm’s work on specific issuers and identifying unusual audit reports.
• Best for: Deeper look at individual companies.

Practical way to compare firms for free

A useful approach is to build a simple scorecard using:

• PCAOB inspection findings
• number/severity of PCAOB or SEC enforcement actions
• frequency of auditor-related restatements
• internal-control material weaknesses among clients
• audit and non-audit fee patterns
• auditor tenure / churn

Important caveat

Audit quality is hard to measure with one metric. A firm with many inspection findings may audit more complex issuers, while a firm with few findings may have a smaller or less complex client base. So compare firms within similar client segments when possible.

If you want, I can also give you:

1. a short ranked list of the best sources by usefulness, or
2. a step-by-step method to compare Big 4 vs. mid-tier firms for a specific market.