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Sustainability

Mattamy Wins A4S Award for Innovation

Lynne Tiernay headshot

Accounting for Sustainability (A4S) is a global organization that seeks to harness the capabilities of the finance and accounting community to power the transition to resilient business models and a sustainable economy.

 

To equip organizational finance teams with skills and technical knowledge they can draw on to embed sustainability into financial processes and decision-making, A4S established the A4S Academy. The Academy’s programming provides senior finance leaders with interactive training, followed by a year-long implementation project to drive organizational change.

 

The A4S Academy Awards were created to acknowledge Academy participants who, through impact, innovation, inspiration, resilience and advocacy, have become visible champions of sustainability in finance. In December 2025, Lynne Tiernay, Vice President of Accounting and Sustainability at Mattamy Asset Management, representing a multidisciplinary team, accepted the A4S Academy Award for Innovation for a pilot program that pioneered a new GHG key performance indicator, enabling builders to compare GHG reductions against a code-built home.

 

This new key performance indicator provides homebuilders with a widely applicable metric that will help the industry to adopt and implement practical solutions for meaningful carbon reduction.

 

Lynne and her colleagues were celebrated for:

 

  • Developing and obtaining assurance for a new, industry-specific metric that compares GHG reductions against a code-built home.
  • Collaborating with Mattamy’s finance and operations teams in designing a data collection strategy that facilitated the delivery of the first publicly assured Scope 3 emissions metrics in the homebuilding industry.
  • Preparing a five-year carbon forecast, which was partially integrated into Mattamy’s five-year financial plan.

 

A4S judges praised Lynne and her team for addressing “a long-standing challenge in the built environment by developing a sector-specific GHG Scope 3 emissions metric for homebuilding that can be publicly assured. The judges recognized the complexity of this task and the skill required to produce a solution that is both practical and capable of being adopted across an industry.”