A third-party audit is an independent examination of your organization’s financial records, internal controls, or security systems, conducted by an outside firm with no financial stake in the outcome. Companies undergo them to satisfy regulators, keep contracts with business partners, and give investors confidence that reported numbers and security practices hold up. What the audit involves, what it costs, and how long it takes depend entirely on which type you need.
The Main Types and When You Need Each
Financial Statement Audits
A financial statement audit confirms that your reported financials are free from errors large enough to mislead investors or lenders. Auditors follow Generally Accepted Auditing Standards, which set the quality benchmarks for how the work is planned, conducted, and reported.1Public Company Accounting Oversight Board. AU Section 150 – Generally Accepted Auditing Standards They test account balances, revenue recognition, asset valuations, and internal controls. For publicly traded companies, the PCAOB sets the standards; for private companies, the AICPA’s Auditing Standards Board does.
SOC Reports
Service Organization Control reports evaluate controls at companies that provide services to other businesses. Three versions exist, each aimed at a different audience.
A SOC 1 focuses on controls relevant to a client’s financial reporting. If your company processes payroll, handles transactions, or touches financial data for other organizations, a SOC 1 tells their auditors your controls won’t introduce errors into their financial statements.
A SOC 2 examines controls related to security, availability, processing integrity, confidentiality, and privacy. Those five categories are the Trust Services Criteria established by the AICPA.2American Institute of Certified Public Accountants. 2017 Trust Services Criteria With Revised Points of Focus 2022 SOC 2 has become the standard SaaS companies, cloud providers, and data centers use to prove their security posture to enterprise customers.
A SOC 3 is a public-facing summary of SOC 2 findings, stripped of the proprietary control details. Companies use it as a general marketing document.
Each SOC report also comes in two flavors. A Type I evaluates whether controls are properly designed at a single point in time. A Type II tests whether those controls actually worked across an observation period, usually six to twelve months. Type II reports carry substantially more weight with customers and regulators because they show sustained performance rather than a snapshot.
Regulatory Compliance Audits
Some audits exist because a specific law or industry rule requires them.
HIPAA audits verify that healthcare organizations and their business associates protect electronic protected health information. Auditors evaluate compliance with the HIPAA Security Rule, testing risk analysis, workforce security, access controls, and incident response.3U.S. Department of Health and Human Services. HIPAA Audit Protocol Civil penalties in 2026 run from $145 per violation for unknowing breaches to $73,011 per violation for willful neglect, with an annual cap of $2,190,294 for repeated violations of the same provision.4Federal Register. Annual Civil Monetary Penalties Inflation Adjustment 2026
PCI-DSS audits apply to organizations handling credit card data. Reviewers test encryption, firewall configurations, access restrictions, and vulnerability management. Card brand fines for non-compliance escalate with duration: first few months of non-compliance may run $5,000 to $10,000 per month, while organizations out of compliance for seven months or longer can face $50,000 to $100,000 monthly, depending on transaction volume.
Information Security Certifications
ISO 27001 certification uses a two-stage external audit of your information security management system. Stage 1 reviews the documentation. Stage 2 is on-site: interviews, evidence review, and testing whether controls actually function in daily operations. After certification, expect annual surveillance audits and a full recertification every three years.
Cloud service providers selling to federal agencies face FedRAMP assessments. Under the FedRAMP authorization process, the assessment must be performed by a FedRAMP-recognized Third Party Assessment Organization. For agency-level authorization, a recognized 3PAO is recommended but not required, though the authorizing official must attest to the independence of any alternative assessor.5FedRAMP Help Center. Are Cloud Service Providers Required to Use a FedRAMP Recognized 3PAO Either way, the assessment must follow all current FedRAMP templates and requirements.
Picking an Auditor You Can Trust
The entire value of the audit depends on the auditor’s independence. A financial relationship or personal stake in the outcome makes the report meaningless. The AICPA defines independence as having two components: independence of mind, meaning outside influences don’t compromise the auditor’s judgment, and independence in appearance, meaning a reasonable third party wouldn’t question their objectivity.
For publicly traded companies, the SEC enforces partner rotation rules. The lead audit partner and concurring review partner rotate off after five consecutive years, followed by a five-year cooling-off period before returning to that client.6Federal Register. Strengthening the Commissions Requirements Regarding Auditor Independence
Before engaging a firm, verify its CPA licenses through the relevant state board of accountancy. Most state boards offer free online license verification. Audit firms are also subject to peer review every three years, in which another firm examines their audit quality. Ask to see the most recent peer review report. Reputable firms accommodate the request without hesitation.
What You’ll Need to Provide
Auditors work from a “Provided by Client” list that spells out every document they need before fieldwork begins. Pulling this together is usually the most time-consuming part of the process on your end, and gaps in the documentation are the single biggest cause of delays and scope creep.
A typical PBC list for a financial statement audit includes:
- A comparative trial balance, general ledger detail, bank statements and reconciliations, and investment activity schedules.
- Aging schedules for accounts receivable and accounts payable as of year-end, reconciled to the trial balance.
- Accrued payroll schedules, quarterly IRS Form 941s, state unemployment reports, and reconciliations of gross pay across filings.
- Depreciation summaries, listings of all fixed-asset additions and disposals during the year, and supporting invoices.
- Schedules of outstanding notes or loans, debt agreements, and amortization schedules.
- Board minutes, budgets, organizational charts, and any new or amended policies and procedures.
- A memo on outstanding legal issues with attorney contact information, copies of contracts and leases, and attorney confirmation letters.
For SOC or compliance audits, the list shifts toward IT evidence: system access logs, network diagrams, encryption configurations, vulnerability scan results, and written security policies. The audit firm usually sends its questionnaire several weeks before fieldwork. Answer with exact system settings and policy numbers, not vague descriptions. If they ask about password complexity, cite the actual Active Directory settings, not a general statement that “we require strong passwords.”
You’ll also need to sign a management representation letter, in which senior leadership formally states that the financial statements and controls are presented accurately. The PCAOB standard requires the letter to be signed by management with overall responsibility for financial and operating matters, typically the CEO and CFO.7Public Company Accounting Oversight Board. AS 2805 Management Representations It has to cover management’s responsibility for fraud prevention controls, completeness of information provided to the auditor, and any known violations of laws or regulations. This letter creates a formal record of accountability, so review it carefully rather than treating it as a formality.
How the Audit Runs
Before testing anything, the auditor sets a materiality threshold: the dollar amount above which an error would likely influence a reasonable investor’s decisions. The PCAOB requires this threshold to be expressed as a specific dollar amount.8Public Company Accounting Oversight Board. AS 2105 Consideration of Materiality in Planning and Performing an Audit Auditors typically calculate it as a percentage of revenue, total assets, or pre-tax income, then set a lower “tolerable misstatement” for individual accounts.
Materiality matters because it determines how deep the auditor digs. A $50 million company might have a threshold of $500,000, meaning the auditor won’t chase a $2,000 discrepancy but will investigate a $300,000 one. Higher-risk areas, such as related-party transactions, get lower thresholds of their own.
Fieldwork begins when the auditor starts working through the documentation, usually through a secure digital portal. They interview key personnel to verify that documented policies actually get followed. This is where the gap between “what the manual says” and “what people actually do” becomes visible, and where most control deficiencies surface. Auditors test by sampling: they pull a set of transactions, access requests, or processing events and check each one against the criteria.
After testing concludes, the auditor issues a draft report detailing observations, deficiencies, or material weaknesses. Management typically has around 30 days to submit a written response or remediation plan for each finding. That response goes into the final report, so stakeholders see both what went wrong and how you plan to fix it. A vague or dismissive response signals to investors and regulators that leadership isn’t taking the findings seriously.
The Opinions and What They Mean
The audit ends with a formal opinion, and the type has real consequences for your reputation, access to capital, and contractual relationships.
- An unqualified (clean) opinion means the financial statements are presented fairly in all material respects. This is what every organization wants.9Public Company Accounting Oversight Board. AS 3101 The Auditors Report on an Audit of Financial Statements
- A qualified opinion says the financials are generally fair, but the auditor identified specific areas where they couldn’t obtain enough evidence or found a departure from accounting standards. A passing grade with a footnote.
- An adverse opinion says the financial statements are materially misstated. This effectively tells stakeholders the reported numbers are unreliable.
- A disclaimer of opinion means the auditor couldn’t obtain enough evidence to form any opinion at all. This usually happens when the organization restricts access to records or when uncertainty is pervasive.
SOC reports work slightly differently. A SOC 2 doesn’t come with a pass/fail label, but the opinion can be unmodified (controls operated effectively) or modified (the auditor found exceptions). A modified SOC 2 won’t necessarily kill a deal, but enterprise security teams will scrutinize the exceptions, and some contracts require an unmodified report as a condition of doing business.
What It Costs
Fees vary based on your size, the complexity of your operations, and the type of report. Rough ranges:
- Financial statement audits. Small businesses under $5 million in revenue typically pay $7,000 to $15,000. Mid-size companies ($5 million to $50 million) fall in the $15,000 to $35,000 range. Larger or more complex organizations start at $35,000 and scale up significantly.
- SOC 2 Type II reports. Early-stage SaaS companies with security-only scope and a three-to-six-month observation period can expect $8,000 to $18,000. Mid-size cloud providers with broader scope pay $20,000 to $26,000. Enterprises or engagements at large firms run $27,000 to $40,000 or more. Adding availability, confidentiality, or privacy criteria pushes fees 30 to 50 percent above security-only.
- SOC 2 Type I reports. Roughly 40 to 60 percent of the Type II cost for comparable scope, because the auditor evaluates a single point in time.
The audit firm’s invoice isn’t the whole cost. Someone on your team will spend serious hours gathering documentation, completing questionnaires, and coordinating interviews. First-timers routinely underestimate this. If you don’t have in-house expertise, audit-readiness consultants charge hourly rates that vary widely by region and specialization.
What Happens If the Findings Are Bad
A clean opinion is a business asset. A bad one cascades.
An adverse opinion or a going-concern qualification, where the auditor questions whether the company can continue operating, functions as a public negative event. Companies that receive going-concern opinions experience credit rating downgrades at meaningfully higher rates than those without. Lower ratings raise borrowing costs and can threaten your ability to refinance existing debt.
Contracts are the other pressure point. Many enterprise agreements and vendor relationships require a current, clean audit report. A modified SOC 2 or a missed PCI-DSS deadline can trigger remediation clauses, restrict your ability to onboard new customers, or provide grounds for contract termination. Independent cybersecurity attestation is increasingly a prerequisite for competing on high-value contracts, so an organization without a clean report loses deals it never hears about.
Audit fees themselves have a feedback loop. Organizations with lower credit ratings or prior audit issues face higher fees on later engagements, because the auditor sees more risk and plans more extensive testing. Skipping fixes early makes every subsequent audit more expensive and more likely to surface new problems.
After the Report: Remediation
Receiving the final report isn’t the end. If the auditor identified deficiencies, you need a concrete remediation plan with assigned owners and deadlines. For PCAOB-regulated firms, quality control criticisms must be addressed to the Board’s satisfaction within 12 months of the inspection report date. Miss the deadline and the portions of the report covering those criticisms become public.10Public Company Accounting Oversight Board. Staff Guidance Concerning the Remediation Process
Effective remediation isn’t just patching the specific finding. The PCAOB evaluates whether the remedial step represents an actual change to the quality control system, whether it addresses the root cause, and whether the organization monitors its own effectiveness afterward.10Public Company Accounting Oversight Board. Staff Guidance Concerning the Remediation Process A quick fix that technically resolves the finding without addressing the underlying problem won’t survive the next cycle.
For SOC 2 engagements, the rhythm is annual. If Year 1 produced a modified opinion, you want the exceptions remediated and a clean observation period logged before the next Type II. Year 2 is where you prove the fix works. Planning remediation early in the cycle, rather than scrambling in the months before the next audit window, is the difference between a smooth engagement and repeating the same findings at higher cost.