Audits are conducted to give an independent, qualified check on information that other people are going to rely on. That includes whether a company’s financial statements are accurate, whether a business is following the laws that apply to it, whether a tax return reports the right amount owed, and whether money entrusted to an organization — by shareholders, lenders, donors, or taxpayers — was handled the way it was supposed to be. The reasons audits are conducted vary by who is asking and what is at stake, but the underlying purpose is the same: verification by someone with no incentive to shade the answer.
To Confirm Financial Statements Reflect Reality
The most basic reason for an audit is to test whether the numbers a company reports actually match what happened. Auditors measure reported figures against a standardized accounting framework, usually Generally Accepted Accounting Principles (GAAP) in the United States or International Financial Reporting Standards (IFRS) for companies reporting internationally. Those frameworks dictate how transactions get recorded, how assets are valued, and when revenue counts as earned.
The focus is on material misstatements, meaning errors or omissions large enough to change how a reasonable person would read the financials. Auditors sample transactions and trace them back to source documents — invoices, contracts, bank records — to see whether the ledger tells the truth. They confirm that assets on the balance sheet exist and are valued correctly, and that revenue and expenses land in the right reporting period. A company that pulls next quarter’s revenue into this quarter looks more profitable than it really is, and catching that kind of timing manipulation is exactly what auditors are trained for.
When that verification works, everyone downstream benefits: investors deciding whether to buy or sell, lenders sizing up creditworthiness, and regulators watching for market abuse. When it fails, the damage travels well past the company itself.
To Meet Legal Reporting Requirements
For publicly traded companies, audits are not optional. Under the Securities Exchange Act of 1934, companies with registered securities must file annual reports on Form 10-K that include financial statements audited by an independent accounting firm.1U.S. Securities and Exchange Commission. Exchange Act Reporting and Registration Foreign private issuers file the equivalent on Form 20-F, also with audited financials, within four months of their fiscal year end.2Securities and Exchange Commission. Form 20-F The CEO and CFO personally certify the financial information in those filings.
The auditor’s conclusion carries real weight. A clean (unqualified) opinion says the statements are presented fairly in all material respects. A qualified opinion carries a specific exception. An adverse opinion says the statements as a whole cannot be relied upon, and a disclaimer means the auditor could not gather enough evidence to form any opinion. For public companies, anything short of a clean opinion creates problems. The SEC treats an adverse opinion as failing to satisfy reporting requirements, which means the related annual filing is considered not timely filed and can restrict the company’s use of streamlined registration forms like Form S-3 and Form S-8, as well as shareholders’ ability to resell stock under Rule 144.3SEC.gov. Financial Reporting Manual – Topic 4: Independent Accountants’ Involvement Missed deadlines and incomplete filings can trigger enforcement actions, trading suspensions, and delisting.
To Verify Tax Liability Is Correct
A tax audit answers a narrower question: did the taxpayer calculate the right amount of tax? The IRS has broad statutory authority to examine books, records, and other data relevant to a return, and it can summon taxpayers and witnesses to testify under oath.4Office of the Law Revision Counsel. 26 USC 7602 – Examination of Books and Witnesses
The consequences of a bad return scale with how bad it looks. The accuracy-related penalty for substantial understatements or negligence is 20% of the underpayment, rising to 40% for gross valuation misstatements.5Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments When the IRS can prove fraud, the civil penalty jumps to 75% of the fraudulent portion of the underpayment.6Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty Willful tax evasion is a felony punishable by up to five years in prison and a fine of up to $100,000 for individuals or $500,000 for corporations.7Office of the Law Revision Counsel. 26 USC 7201 – Attempt to Evade or Defeat Tax
Individual audit rates are low overall — the IRS examined about 0.2% of individual returns for tax year 2022 — but rise sharply with income, reaching 4.0% for taxpayers earning $10 million or more.8Internal Revenue Service. IRS Data Book 2024 The point of the examination is the same regardless of who gets picked: confirm that reported income, deductions, and credits match the underlying facts.
To Test the Systems Behind the Numbers
An audit looks not only at whether the final numbers are right but at whether the systems that produced them can be trusted. Internal controls are the procedures an organization uses to prevent fraud, catch errors, and make sure transactions are recorded correctly as they happen. A textbook control weakness is letting one person both approve payments and record them, because no second set of eyes catches theft or mistakes.
For public companies, evaluating those controls is a legal requirement. Section 404 of the Sarbanes-Oxley Act requires each annual report to include a management assessment stating that management is responsible for maintaining adequate internal controls over financial reporting and evaluating their effectiveness at fiscal year end.9Office of the Law Revision Counsel. 15 USC 7262 – Management Assessment of Internal Controls For large accelerated and accelerated filers, the external auditor must also independently attest to that assessment, producing two separate evaluations of the same control environment. When auditors identify a material weakness — a deficiency severe enough that a material misstatement could go undetected — the company has to disclose it publicly.
To Unlock Loans and Investment
Outside the regulatory world, audits are conducted for a very practical reason: they help organizations get funding. Commercial lenders routinely require audited financial statements before approving business loans, especially for larger or longer credit facilities. A bank extending multi-year credit wants independent confirmation that cash flow and asset values aren’t overstated.
Without audited financials, lenders may charge higher interest, lend less, or decline the application outright. Research on private debt markets found that lenders charge an average of 17 basis points more after a modified audit opinion and are more likely to demand collateral. Going-concern opinions, where the auditor flags doubt about the company’s ability to survive, push loan spreads up by an average of 107 basis points, and lenders shrink the size of what they will offer. Venture capital and private equity firms apply the same logic during due diligence, and an audit is typically a prerequisite in any merger or acquisition.
To Account for Public Money
When an organization spends money that came from taxpayers, the audit’s job shifts from testing financial accuracy to confirming that funds went where they were supposed to go. Federal law requires any non-federal entity — a state, local government, or nonprofit — that spends $1,000,000 or more in federal awards during a fiscal year to undergo a single audit covering both the entity’s financial statements and its compliance with federal award requirements.10eCFR. 2 CFR Part 200 Subpart F – Audit Requirements The underlying statute, the Single Audit Act, sets a floor of $300,000 but authorizes the OMB Director to adjust the threshold upward, which is how it reached $1,000,000, effective for fiscal years beginning on or after October 1, 2024.11Office of the Law Revision Counsel. 31 USC Ch 75 – Requirements for Single Audits Entities spending less than $1,000,000 in federal awards are exempt from the federal audit requirement, though their records must still be available for review.
Public-money audits also follow a stricter rulebook. The Government Accountability Office publishes Generally Accepted Government Auditing Standards, known as the Yellow Book, which add requirements on top of standard auditing practices. Yellow Book audits examine compliance with contracts and grant agreements and require reporting on internal controls and compliance whether or not problems are found.12United States Government Accountability Office. Government Auditing Standards 2024 Revision Government auditors may also apply lower materiality thresholds than private-sector auditors, reflecting the higher accountability that comes with spending public funds.
Who Performs the Audit
Not every audit comes from outside the organization. Internal audit departments live within a company and continuously evaluate risk management, operational efficiency, and compliance with internal policies. Internal auditors report to senior management and the board’s audit committee, and their work runs throughout the year. They look for process improvements and control gaps before those gaps turn into losses.
External auditors are independent professionals hired specifically to opine on the fairness of the financial statements. They report to shareholders through the audit committee, and their engagement centers on the annual reporting cycle. Independence is the entire basis for an external audit’s credibility. An opinion from someone on the company’s payroll does not carry the same weight with lenders, investors, or regulators, which is why the two roles exist side by side rather than one replacing the other.