Materiality-Weighted Portfolio Carbon Footprint: A More Accurate Measure for Transition Risk

The total carbon footprint of a portfolio is often used to assess both climate impact and transition risk. However, we found that these goals require different approaches. While every metric ton of CO₂ affects the climate equally, not all emissions carry the same financial risk. Transition risk depends on where emissions originate and the business context. A materiality-weighted carbon footprint—focused on emissions most exposed to business pressure by sub-industry—provides a clearer risk signal. For example, value-chain (Scope 3) emissions often contribute less to risk than direct (Scope 1) emissions. In the MSCI ACWI Index, this approach retains 78% of Scope 1+2, 62% of Scope 3 downstream, and only 6% of Scope 3 upstream emissions. Over the past decade, materiality-weighted emissions showed stronger links to equity outperformance, earnings, and credit risk than total emissions, even after controlling for industry and style. This may explain why past academic studies using total emissions found limited and often diverging links to financial performance.