Can one firm do both, prepare and assure?

Short answer

Sometimes. The test is whether that firm will also assure the report. A firm that will assure it cannot prepare it for a public interest entity, because APES 110 prohibits the self-review threat outright. For other entities the firm judges it case by case. A firm that will not assure it faces no such constraint.

On this page

One question decides most of it
It cannot, clearly
It depends
It can
The decision
The option most readers miss
What your firm can still do while remaining your assurer
What to ask, and get in writing
Where Carbonhalo fits
Related questions
Sources

All questions

Back to the FAQ

One question decides most of it

Ask the firm whether it intends to seek the sustainability assurance engagement. That single answer sorts you into one of three situations, and the situations are genuinely different. Firms often give the conservative answer without explaining which situation applies, which leaves the reader thinking the law is tighter than it is.

It cannot, clearly

The firm will be the assurance provider on your sustainability report, and you are a public interest entity.

Preparing a disclosure you will later assure means evaluating your own earlier work. APES 110 calls that a self-review threat. Where a non-assurance service to a public interest entity audit client would create one, the Code treats it as a threat that cannot be eliminated and that safeguards cannot reduce to an acceptable level. The service is prohibited. There is no judgement to make and no safeguard to design.

This is the common Group 1 and Group 2 case, which is why most readers meet the prohibition rather than the judgement.

It depends

The firm will assure the report, and you are not a public interest entity.

Here the prohibition does not bite automatically. The firm applies the conceptual framework: it identifies the threat, evaluates whether it is at an acceptable level, and applies safeguards if it can. The decision is the firm’s, not yours.

Two things hold regardless. The management-responsibility prohibition applies absolutely, to every audit client and every service, so the firm cannot make your decisions or take your judgements whatever the entity type. And many firms decline anyway, because the risk of being wrong is carried by them and not by you. A conservative answer in this situation is a risk-appetite answer, not a legal one, and it is reasonable to ask which it is.

It can

The firm is not your assurance provider and is not inside your assurance provider’s network.

APES 110’s independence provisions do not bind it in relation to you, and the constraint becomes commercial rather than ethical. Judge it on capability, documentation quality and price.

Two checks before you rely on that. Check the network, not the brand. The constraint follows the network, and that matters most in the mid-tier, where Australian firms sit inside international networks that are not obvious from the name. Ask directly and get the answer in writing. Check what else they do for you, because another assurance engagement, an internal audit function or an expert role can change the analysis.

The decision

Will the firm assure your report?

Are you a public interest entity?

Can it prepare?

Yes

No. Prohibited outright under APES 110

Yes

Firm’s judgement under the conceptual framework. Management responsibility still prohibited

No, and not in your assurer’s network

Either

Yes. The constraint is commercial, not ethical

The threat attaches to the work, not to the individual. A different team inside the same firm does not cure it for a public interest entity. Neither does a different member firm inside the same network. This is the point most often got wrong in proposals, and it is worth stating plainly because the fix people reach for first does not work.

Dates to hold. A new Part 5 of APES 110 dealing specifically with sustainability assurance took effect on 1 January 2026. Its value-chain provisions take effect from 1 July 2028.

The option most readers miss

You are not obliged to use one firm for both audits. Corporations Act s 324AA(1) expressly permits a company, registered scheme or retail CCIV to appoint a different auditor for the sustainability report from the auditor of the financial report. Only a registrable superannuation entity is locked to a single auditor, under s 324AA(2). Either way the auditor must be a Registered Company Auditor.

That gives you a fourth option: appoint a separate assurance provider, which frees your usual firm to prepare. It is legitimate and it carries real costs. Two firms means two fee bases and two engagement teams. Your sustainability report and your financial report must be consistent, so connectivity between them becomes something you manage rather than something that happens. Each auditor may need access to the other’s evidence, and ASIC has noted that where auditors cannot access each other’s work a scope limitation can result.

It is on the table. An audit committee should decide it deliberately rather than inherit it.

What your firm can still do while remaining your assurer

The line falls at authorship. Work that stops short of it is often still available:

training your finance team
explaining what the requirements are
commenting on a methodology you selected
a readiness or gap assessment
reviewing a draft you prepared and own

Work that crosses it generally is not: building the inventory, selecting the judgements, drafting the disclosures, or anything your team could not explain as their own.

What to ask, and get in writing

Do you intend to seek the sustainability assurance engagement? Ask first. It decides the rest.
Do you treat us as a public interest entity for APES 110 purposes, and on what basis?
If you are declining, is that the Code, your own risk appetite, or capacity? They lead to different next steps.
Which firms are inside your network in Australia?
Exactly which services can you provide to us while remaining our assurer?

Where Carbonhalo fits

Carbonhalo prepares mandatory climate reports under AASB S2 for Australian businesses filing for the first time. Carbonhalo does not provide assurance to anyone, which is why it sits cleanly on the preparation side of the line regardless of which of the three situations above applies to you.

Terms used in this answer

Self-review threat

APES 110

Auditor independence (climate reporting)

Assurance provider (vs auditor)

Preparer / assurer separation