Method & Standard
IDW S 1 in Business Valuation
IDW S 1 is a central valuation standard in Germany. Yet the decisive point is always valuation purpose: standardization does not replace proper theoretical and practical positioning.
What is IDW S 1?
IDW S 1 is the valuation standard of the Institute of Public Auditors in Germany. It describes principles, valuation occasions, valuation functions, and requirements for methodological transparency and documentation.
Why IDW S 1 matters in practice
The standard is especially important in Germany for reports, valuation opinions, and standard-oriented valuation contexts. It regularly appears in business sales and acquisitions, shareholder conflicts, inheritance and tax matters, and near-legal settings.
Objectified and subjective value
A central distinction under IDW S 1 is between objectified business value, subjective decision value, and compromise value. This distinction matters because different valuation functions require different value concepts.
Objectified business value
A typified and neutralized value, especially relevant for standardized valuation purposes.
Subjective decision value
The individual threshold of advantage from the perspective of the concrete valuation subject.
Typical valuation contexts
IDW S 1 is especially relevant in the following situations:
- Business sale and acquisition
- Shareholder disputes, compensation, and near-legal proceedings
- Tax, inheritance, and succession contexts
Possible misconceptions
"IDW S 1 always delivers one objectively correct value."
No. Even under IDW S 1, one must distinguish between valuation purpose and valuation function. Different functions lead to different value concepts.
"Objectified value and decision value are the same."
Not necessarily. The objectified value is a standardized reference value, whereas the subjective decision value is the individual threshold of advantage.
"An IDW S 1 valuation no longer needs plausibility review."
It does. Even under recognized standards, assumptions, data quality, consistency, and economic robustness must still be examined critically.
When a review is useful
A review is especially useful where a report has major economic consequences, where assumptions are disputed, or where one must clarify whether the chosen standard and method actually fit the assignment.
Questions for orientation on IDW S 1
Is IDW S 1 a law?
No. IDW S 1 is not a law, but a professional standard. It is nevertheless highly influential and often practically decisive.
Which methods are admissible under IDW S 1?
At the core, especially capitalised earnings methods and DCF methods in their relevant variants. Further approaches may also be used for plausibility purposes.
Why is the distinction between objectified and subjective so important?
Because it determines whether a typified reference value or the individual value of a concrete valuation subject is meant. This distinction is economically important for correct decisions.
Do you need a robust positioning on IDW S 1?
I support you in business valuations and in the technical review of existing reports — structured, transparent, and purpose-oriented.