Statutory Audits in the Mittelstand: Who Is Audited and What It Delivers

Why the audit requirement is more than a mandatory appointment

When a business grows, a letter from the tax adviser arrives at some point: next year, the financial statements must be audited. For the owner, this means additional costs, questions from outsiders, and one more appointment in spring. Rarely does anyone ask what they get for it and what others use the result for.

Yet a great deal depends on this audit. Banks, credit insurers, buyers, and co-owners read the audit opinion as a sign that they can trust the numbers. This article therefore pursues one question: Who in the Mittelstand, Germany's small and mid-sized business sector, must have their financial statements audited, and what does the audit actually deliver?

To answer it, we first clarify the requirement and the terms, then present the expectation gap as a thinking model, look at what studies say about the benefit of an audit, and finally derive how an owner can make the most of it.

Who must be audited? The size classes of the German Commercial Code

Under Section 316 of the German Commercial Code (HGB), corporations that are not small must have their annual financial statements and management report audited by a statutory auditor. Without an audit, the financial statements cannot be formally adopted. The same applies to partnerships without a natural person as fully liable partner, typically the GmbH & Co. KG, a limited partnership whose general partner is a limited company (Section 264a HGB). Very large companies of other legal forms are covered by the Disclosure Act (PublG).

Three criteria determine the size class. A company belongs to a class if, on two consecutive balance sheet dates, it does not exceed at least two of three thresholds. The thresholds for total assets and revenue were raised by about 25 percent in April 2024; those for employees remained the same.

For many owners, the 2024 increase shifted the requirement. A GmbH with 40 employees, 14 million euros in revenue, and 8 million euros in total assets exceeds only one threshold and is small. It does not need an audit. The two-year rule matters: a single strong year does not yet change the class.

What the audit covers, and what the audit opinion says

Under Section 317 HGB, the audit must be planned so that misstatements and violations that have a material effect on the company's picture are detected with conscientious professional practice. Material means large enough to influence the decision of a reasonable reader. The auditor works with samples, confirmations from third parties, inquiries, and analyses. They therefore provide reasonable, not absolute, assurance.

The result is stated in the audit opinion under Section 322 HGB. It can be unqualified, qualified, or withheld. More detailed is the long-form audit report under Section 321 HGB, which is not published and goes to management, supervisory bodies, and, at a GmbH, the shareholders. It describes findings, weaknesses, and risks and is often the more valuable document for owners. Who may audit is governed by Section 319 HGB: certified public accountants and audit firms, and for medium-sized GmbHs also sworn auditors (vereidigte Buchprüfer).

How far these limits reach in practice is shown by the Wirecard case, whose financial statements had received unqualified opinions for years. Chronicle of an accounting scandal recounts the sequence of events. Why an auditor is paid by the audited company and what conflicts follow is described in How independent are auditors?.

The thinking model: Porter's expectation gap

When people ask after a collapse where the auditors were, there is almost always an expectation gap behind it: the distance between what readers expect from an audit and what it delivers. The New Zealand researcher Brenda Porter defined the term more precisely in 1993. Church and Prinsloo (2026) summarize her model as follows: the gap has two parts.

An everyday analogy helps. A car's roadworthiness inspection confirms that brakes, lights, and steering meet the requirements on the day of the test. It does not say that the car will not break down before the next inspection, and the inspector does not take the engine apart. Anyone who expects that experiences a reasonableness gap. Anyone who gets a sticker although the brakes were already failing at the time experiences a performance gap.

An audit opinion is a judgment about financial statements, not a seal of quality for a company.

What readers in the Mittelstand expect from the audit

Most research on the expectation gap looks at listed companies. Church and Prinsloo (2026) therefore deliberately interviewed users of the financial statements of unlisted companies. In 20 interviews in South Africa's Free State province, they spoke with managers, shareholders, bank credit officers, and staff of the tax authority.

Three findings are revealing for owners. First, respondents did not expect the auditor to uncover every fraud, unlike what many studies show for listed companies. Second, however, they did expect the auditor to confirm compliance with all laws and the effectiveness of internal controls, which is more than a financial statement audit must deliver. Third, shareholders relied on the auditor to defuse conflicts between owners and management, for example in family businesses. The authors themselves stress that their results should not be generalized.

I consider the third finding the most important. In a business where one shareholder manages and others only see figures, the audit is often the only independent view. But it can fill this role only if the shareholders know what was audited and what was not. What such structures look like is described in Corporate governance for small businesses.

Cost or value? Two readings on the benefit of an audit

Whether an audit costs more than it brings is a real question for small companies, because many could choose to be audited voluntarily.

The second reading is supported above all by Minnis (2011). He examined a large database of unlisted US companies that were not required to be audited. Audited companies had significantly lower costs of debt, and lenders gave audited figures more weight when setting interest rates. As a mechanism, he found that accruals in audited statements better predicted future cash flows. Compagnie, Jeny, and Orens (2026) even found among large unlisted companies in Belgium that lenders demanding reliable statements charged lower interest when the auditor also provided advice. With very high lender demands, this effect disappeared.

The first reading is supported by the critique of Cassar (2011), who commented on Minnis's study. He doubts that cause and effect can be cleanly separated: companies that choose to be audited differ from others in other ways too. I nevertheless consider the finding robust in direction, not in size. That banks trust audited figures more is consistent with practice, in which banks require insight into the financial circumstances for larger loans. How banks decide is described in How banks decide on loans.

Audit, review, compilation: the gradations for small businesses

Anyone not subject to audit has more options than an audit or nothing at all. The profession knows gradations that differ in assurance and effort.

Which level fits depends on the reader. A bank with an overdraft facility often needs less than a buyer taking over a stake. It makes sense to ask before deciding who reads the figures and what they decide with them.

The audit map: how to get more out of the audit

Whether mandatory or voluntary, the benefit depends less on the auditor than on preparation. I call the following approach the audit map, because it sets out in advance where the auditor should look closely.

1. Clarify the requirement

   Check the three size criteria for the last two balance sheet dates with your tax adviser. Plan in good time when a threshold approaches.

2. Name the readers

   Write down who reads the financial statements: bank, credit insurer, shareholders, buyers. Ask what assurance they need.

3. Mark the risks

   Tell the auditor the three items you are unsure about yourself, such as inventory valuation, large receivables, or new contracts.

4. Keep the auditor independent

   Have shareholders or an advisory board help select the auditor and know the fee. Whoever prepares does not audit.

5. Use the audit report

   Read the report in full and assign an owner and a deadline for every weakness mentioned.

The third step reduces the performance gap, because the auditor directs time to where risks lie. The fourth follows from the basic conflict that An advisory board for the Mittelstand and The Big Four illuminate from different angles. How much latitude the accounting decisions have that the auditor assesses is shown in Earnings management and accounting fraud.

Conclusion: the audit delivers a lot, but not everything

To the guiding question: medium-sized and large corporations and GmbH & Co. KG partnerships must be audited, since 2024 according to significantly higher thresholds. The audit provides reasonable assurance that the financial statements are free of material errors. It is no guarantee against fraud and no judgment about the company's future. Many disappointments are explained by the expectation gap: readers expect more than the audit must deliver, and sometimes it delivers less than it should.

Studies suggest that audited figures carry more weight with banks, even if the size of the advantage is disputed. For an owner, it follows that anyone who experiences the audit as a mandatory appointment pays for an opinion. Anyone who prepares it and uses the report gets an independent view of their own business.

• Compare the three size criteria for the last two balance sheet dates with the thresholds.
• Write down who reads your financial statements and what assurance they need.
• Name three risk items to the auditor or tax adviser before the next audit.
• Assign owners and deadlines to the recommendations from the last audit report.