As we approach the end of the 2025 calendar year, Group 1 companies move closer to lodging their first mandatory Sustainability Report under the Corporations Act 2001 (ASIC RG 280) and AASB S2 Climate-related Financial Disclosures (AASB S2 Standard).

For many organisations, the past 6–12 months have focused on awareness, mobilisation and early capability building. The next six months will determine whether your first Sustainability Report is assurance ready (AUASB SSA 5000) and whether your underlying processes can withstand Board scrutiny, investor expectations and external audit.

Below are the key actions C-suite leaders and Boards should prioritise now to finish the year strong and set up Q1 2026 for success.

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1. Finalise your integrated reporting timetable

Your sustainability report must align with your financial statement lodgement and the external audit cycle. Companies should now be:

• Developing a consolidated end-to-end reporting timeline covering traceable data collection, governance milestones, internal and external reviews, and draft and final report preparation.
• Preparing a pro-forma sustainability report and circulating your climate statement and disclosures to Executive, Board and external auditors for early review and feedback.
• Ensuring alignment with your external audit timeframe to support a “no surprises” approach, including review of your methodology, key assumptions and judgements, data sources, climate statement and notes.

A clear timeline ensures coordination across finance, sustainability, risk, operations and audit teams and reduces last-minute pressure during reporting season.

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2. Validate your governance, controls and oversight framework

Mandatory sustainability reporting brings increased scrutiny on governance, controls, data reliability, and the quality of assumptions and judgements. Companies should now ensure:

• Clear roles and responsibilities are documented across Executive, Board and Committees, with updated terms of reference(s).
• A formal skills and capability assessment identifies whether leaders have the competence to oversee climate-related strategy, risks and opportunities, supported by targeted Board and Executive training where required.
• Evidence exists of governance protocols throughout the period, including documented challenge, critical review and decision-making across strategy, climate-related risks and opportunities, risk management, metrics and targets.

Strong governance is one of the biggest indicators of audit readiness and organisational resilience.

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3. Stress test climate-related data, systems and controls

Climate-related data remains the most common risk area, given it is sourced from multiple systems, teams and operational processes. Before year-end, companies should have:

• Identified key metrics to be reported, including a full inventory of Scope 1 and 2 emissions and other climate-related metrics, supported by clear activity data, estimates and assumptions.
• Developed a robust Basis of Preparation, documenting sources, methodologies, estimates, assumptions and calculation approaches.
• Completed data quality reviews covering calculations, reconciliations and consolidation processes.
• Identified and addressed technology or system gaps, particularly where spreadsheets or manual processes introduce error risk or insufficient audit trails.

A coordinated plan, strong governance and early data validation supports a smooth first-year reporting cycle and reduces assurance findings.

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The first year of mandatory sustainability reporting represents a significant uplift in expectations around governance, strategy and climate-related decision making, as well as data quality, risk management and audit readiness.

Key lodgement date reminders:

Reporting entities must lodge their annual reports with ASIC:

• within three months after the end of the financial year for a disclosing entity, registered scheme or RSE; and
• within four months after the end of the financial year for other entities.

For relevant reporting entities with a financial year that ends on 31 December 2025, the first sustainability reports will need to be lodged by:

• 31 March 2026 for disclosing entities; and
• 30 April 2026 for other entities.

For relevant reporting entities with a financial year that ends on 30 June 2026, the first sustainability reports will need to be lodged by:

• 30 September 2026 for disclosing entities; and
• 31 October 2026 for other entities.

If your organisation needs support, Azab Business Advisory can guide you every step of the way, combining deep financial reporting, sustainability, risk and audit experience.