Scope 3 Gets Rewritten. Your Baseline Just Expired.

The GHG Protocol has not updated its Scope 3 Standard since 2011. In March 2026, it published a structural revision that adds a new emissions category, sets a 95% coverage threshold, and bans the most common allocation shortcut in supply chain accounting.

13 May 20263 min read8 views

Scope 3 rewritten — concentric rings showing the new 95% coverage threshold and Category 16

At a Glance

▸ First revision to the Scope 3 Standard since 2011 (March 2026 Phase 1 Progress Update)

▸ 95% coverage threshold replaces selective category reporting

▸ New Category 16: facilitated emissions, captures insurers, architects, platforms, franchisors

▸ Category 15 (Investments) broadened: investee Scope 3 now mandatory

▸ Diversified supplier allocation banned. Data quality disaggregation required

▸ Public consultation mid-2026. Final standard late 2027. SBTi v2 will reference it

The Scope 3 Standard became the most cited and least implemented piece of carbon accounting infrastructure in the world. Over fifteen years, companies used its flexibility to measure selectively: pick a few categories, exclude the difficult ones, call it compliant. The March 2026 Phase 1 Progress Update closes that gap.

Three changes matter most. A 95% coverage threshold that stops companies cherry-picking categories. A sixteenth category for facilitated emissions. And a ban on diversified supplier allocation, the shortcut that let companies estimate supply chain emissions using revenue share as a proxy.

What Changed

The 95% Rule. Under the current standard, companies decide which categories are “relevant” and report only those. The revision replaces relevance with coverage: account for 95% of total Scope 3, or explain why you cannot. Categories cannot be excluded because they are difficult to measure.

Most companies measure the front door of their Scope 3 and call it done. The new rules say you measure 95% of the house.

Category 16: Facilitated Emissions. A three-part test: (a) your services enable, initiate or influence the emissions; (b) you do not own or control the emitting asset; (c) you earn transactional income from the activity. Category 15 asks: do you own a piece of the company that emits? Category 16 asks: did your service make the emission happen?

Who is captured:

Sector	Why Category 16 Applies
Insurance underwriters	The policy enables the insured activity; premium income is transactional
Architects & engineers	The design specifies materials, HVAC and operational energy for 50 years
Platform operators	The marketplace connects buyer and seller of carbon-intensive goods
Franchisors	The brand and operating model dictate the franchisee’s energy profile
Banks (project/trade finance)	Financing enables the carbon-intensive activity without ownership

Category 15 Broadened. Originally for financial institutions only, now applies to any company holding equity or debt. Investee Scope 1, 2 and 3 becomes mandatory, no longer optional. For fund managers, every portfolio company’s full value chain feeds into the investor’s own Scope 3.

Diversified Supplier Allocation Banned. The most common spend-based shortcut, spreading a supplier’s total emissions across revenue share, is no longer permitted. Companies must use supplier-specific data or, at minimum, industry-average factors at commodity level.

Data Quality Disaggregation. Companies must report the proportion of their Scope 3 inventory from primary data (supplier-specific), secondary data (industry-average) and modelled data (spend-based). Data quality becomes visible to boards and auditors for the first time.

Current vs. Revised

Dimension	Current (2011)	Revised (2027)
Coverage	Company selects categories	95% of total Scope 3
Categories	15	16 (facilitated emissions)
Cat 15 scope	Financial institutions	All equity/debt holders
Investee Scope 3	Optional	Mandatory
Supplier allocation	Diversified permitted	Diversified banned
Data quality	Not required	Mandatory disaggregation

So What. Who Is Affected

1. Fund managers and asset owners. Investee Scope 3 becomes mandatory. The 95% threshold means coverage cannot cherry-pick low-emitting holdings. Managers reporting Scope 1 and 2 only will need to restate.

2. Insurers. Underwriting carbon-intensive activities now falls under Category 16. If the policy enables the activity and you earn premium income, the emissions are in scope.

3. Architects and design consultants. The building you design specifies materials and energy systems for decades. Category 16 asks whether your design influenced the emissions.

4. Any company with an SBTi target. SBTi v2 will reference the revised standard. Existing baselines will need to be restated. The five-year mandatory review means no target is grandfathered.

A baseline that covered six categories and excluded investee Scope 3 is not a baseline under the revised standard. It is a starting point that needs to be rebuilt.

Timeline

The revision is not final. The March 2026 document is a progress update. Public consultation draft expected mid-2026. Final standard late 2027. But the direction is locked. Companies that wait for the final standard will be restating baselines under time pressure. Companies that start now will have a defensible inventory when it lands.