What is a significant component?
Under the pre-revision ISA 600, the group engagement team classified each component as significant or non-significant using two tests. A component met the quantitative test if it was individually financially significant to the group, typically measured against consolidated revenue or total assets. It met the qualitative test if it was likely to include significant risks of material misstatement of the group financial statements. ISA 600.27 (pre-revision) required a full-scope audit or audit of specific account balances for every significant component. For non-significant components, the standard permitted analytical procedures at group level.
ISA 600 (Revised), effective for periods beginning on or after 15 December 2023, replaced this binary classification with a single risk assessment across the group. The group engagement team identifies and assesses risks of material misstatement of the group financial statements and determines the appropriate audit response at each component. A component with concentrated risk in one account balance gets targeted procedures on that balance. One with pervasive risk across multiple assertions gets broader work. The significance label is gone. The risk assessment drives everything.
Key Points
- The revised standard eliminated the significant component classification entirely.
- Risk-based scoping replaced the binary significant/non-significant split.
- Firms still using the old classification do not comply for periods starting 15 December 2023 onward.
- The nature of work on each component now follows from the group risk assessment, not a significance label.
Worked example: Schreiber Automotive GmbH
Client: German automotive group, FY2024, consolidated revenue €280M, IFRS reporter, four subsidiaries, with two in Germany and one each in Poland and Romania.
Under the pre-revision approach
Classify by size: Schreiber Powertrain GmbH (revenue €160M, 57% of consolidated) and Schreiber Components Polska Sp. z o.o. (revenue €72M, 26% of consolidated) would both be significant on the quantitative test. The two remaining subsidiaries (combined revenue €48M, 17% of consolidated) would be non-significant.
Apply the consequence: full-scope audits required for the two significant components. Analytical procedures at group level for the two non-significant components.
Under ISA 600 (Revised)
The group engagement team skips the classification step. Instead, it identifies where risks of material misstatement sit across all four components. If the Romanian subsidiary holds a material amount of slow-moving inventory with estimation uncertainty, the team designs specific procedures on that inventory balance regardless of the subsidiary's size. The Polish subsidiary might need targeted procedures on revenue recognition if intercompany pricing is complex, even though the old approach would already have scoped it in. Size alone no longer determines scope.
The risk-based approach produces a more targeted scope. If the team had applied the old classification, the Romanian subsidiary's inventory risk would have been covered only by analytical procedures at group level, which would not have been sufficient.
What reviewers and practitioners get wrong
The most common transitional error is carrying the old significant/non-significant classification into files that fall under ISA 600 (Revised). Firms that updated their group audit templates before the effective date caught this. Firms that did not are producing non-compliant documentation for periods beginning on or after 15 December 2023.
Some teams apply the risk-based scoping approach but still use the word "significant" as an informal label in their working papers. Reviewers, both internal and regulatory, read this as evidence that the old methodology was applied. The terminology matters as much as the approach.
Significant component vs. risk-based scoping
| Dimension | Significant component (pre-revision) | Risk-based scoping (ISA 600 Revised) |
|---|---|---|
| Classification method | Binary: significant or non-significant | No classification; risks identified across all components |
| Primary driver | Size relative to group, or presence of significant risks | Location and nature of risks of material misstatement |
| Work on small components | Analytical procedures at group level permitted | Targeted procedures required if risks are identified |
| Documentation focus | Justify the classification | Justify the risk assessment and the audit response |
| Typical inspection finding | Classification threshold not documented | Risk assessment not granular enough to drive scope |
Key standard references
- ISA 600.9(m) (pre-revision): Defined the significant component classification.
- ISA 600.27 (pre-revision): Required full-scope audits or audits of specific balances for significant components.
- ISA 600 (Revised).26–29: Replaced the classification with risk-based scoping across all components.
Related terms
Related reading
Frequently asked questions
Is the significant component classification still valid?
No. ISA 600 (Revised), effective for periods beginning on or after 15 December 2023, eliminated the significant component classification entirely. Firms still using the old binary split for periods starting after that date are producing non-compliant documentation.
What replaced the significant component approach?
ISA 600 (Revised) requires a risk-based scoping approach. The group engagement team identifies and assesses risks of material misstatement across all components and determines the appropriate audit response at each component based on where the risks sit, not on a significance label.