Last updated: 13 May 2026
Short answer: Microsoft's 2025 supplier data-integrity guidance asks suppliers to address total-company emissions and Service-Level Accounting, or SLA, emissions through either an independent assurance route or a third-party consultant-letter route. Suppliers should first review the exact Microsoft request or portal wording, then confirm the required total-company/SLA scope, Scope 1, Scope 2, and Scope 3 categories 1 through 8, service/reference-unit data, evidence, methodology documentation, and whether a consultant letter or independent assurance path applies. Keslio supports the consultant-letter route; independent assurance is separate.
When a Microsoft supplier GHG reporting request lands with a finance, operations, HR, procurement, or account team, it can look deceptively simple. The customer is asking for greenhouse gas emissions information, but the practical work behind the response may involve activity data, emission factors, methodology choices, total-company emissions, service-level accounting, supporting evidence, and a consultant letter.
That is especially difficult for suppliers that do not have an internal sustainability team. The request may arrive through a portal, procurement contact, contract addendum, supplier sustainability questionnaire, or forwarded customer email. The team receiving it may not immediately know whether Microsoft is asking for company-level emissions, service-level emissions, a consultant-letter route, independent assurance, or another response path.
Have a Microsoft supplier GHG request in front of you? Share the request and Keslio will review it for free. We will help confirm whether it appears to require consultant-letter support, independent assurance, service-level accounting, or another response path. Review your Microsoft supplier GHG request.
Why Microsoft suppliers are being asked for GHG emissions data
Large companies increasingly ask suppliers for emissions data because supply chains often represent a significant share of their climate impact. Supplier data can support Scope 3 accounting, procurement decisions, customer reporting, decarbonization programs, and annual sustainability disclosures.
For suppliers, the request can create a new reporting obligation without much internal preparation. A service business may need to collect utility bills, fuel use, travel records, employee commuting estimates, purchased goods and services data, cloud or software usage information, and finance records that support a defensible GHG calculation.
The challenge is not only the calculation. The supplier also needs to understand what Microsoft is actually asking for, how the response should be documented, whether the response needs to be broken down by service, and what level of external support is expected.
What Microsoft's 2025 data-integrity guidance changes
Microsoft's public 2025 Disclosure Cycle Procurement Sustainability Data Integrity Requirements describe data-integrity expectations for both total-company emissions and Service-Level Accounting, or SLA, emissions. The guidance gives suppliers assurance and consultant-letter options for total-company emissions and for SLA emissions, with the submission details depending on the applicable Microsoft request, portal wording, and supplier situation.
That makes the first read of the request important. Suppliers should expect total-company emissions and service-level emissions associated with goods or services delivered to Microsoft to be part of the conversation unless their specific request says otherwise. For the service-level path, Microsoft guidance points to emissions broken out by each service, reference unit volume, and the applicable service information. In practice, that can require allocation logic in addition to the company footprint.
The same guidance also points suppliers to Scope 1, Scope 2, and Scope 3 categories 1 through 8 for the relevant total-company or service-level option, even where a category is zero or immaterial. Suppliers should not assume that a simple Scope 1 and Scope 2 summary will be enough without checking the request.
Why the wording of the Microsoft request matters
Before starting calculations, suppliers should confirm the exact language in the Microsoft request. The response path can differ depending on whether Microsoft is asking for company-level emissions, service-level emissions, a consultant letter, independent assurance, supporting documentation, a portal response, or a combination of those items.
A broad instruction to report annual GHG emissions is different from a request to calculate emissions connected to a specific service, project, contract, or reference unit. A request for a third-party consultant letter is also different from a request for independent assurance. Reading the wording carefully at the start helps avoid over-scoping the work or preparing the wrong evidence package.
Keslio's free review is designed to interpret the request first, then quote the right fixed-fee support project. The first step is clarity on the request, not a rushed spreadsheet.
Consultant letters are not the same as independent assurance
Some Microsoft supplier requests may involve independent assurance, while others may allow a third-party consultant letter. These are not the same.
A consultant letter documents the consultant's support in preparing emissions calculations and related methodology. It can sit alongside the GHG workbook, methodology note, service-level allocation logic, and evidence pack when the supplier is using a consultant-letter route.
Independent assurance is a separate service performed under assurance standards by an independent assurance provider. It is closer to an assurance engagement than advisory support. Keslio supports the consultant-letter route and can help suppliers identify early if their request appears to require independent assurance or another provider.
What a Microsoft supplier may need to prepare
The exact data depends on the request, the supplier's business model, the reporting period, and the service-level accounting basis. In many cases, suppliers should expect to organize information for Scope 1, Scope 2, and Scope 3 categories 1 through 8, even where a category is zero or immaterial.
- Scope 1 activity data, such as fuel used in company-controlled vehicles or facilities.
- Scope 2 electricity or purchased energy data, supported by invoices or meter records where available.
- Relevant Scope 3 data, such as purchased goods and services, capital goods, fuel-and-energy-related activities, upstream transportation and distribution, waste, business travel, employee commuting, upstream leased assets, cloud usage, or other categories where applicable.
- Entity, location, reporting-period, and organizational-boundary details.
- Service, project, contract, reference-unit, or delivery-volume data where service-level accounting is required.
- Any portal wording, supplier instructions, deadlines, templates, or contract language from Microsoft.
- Evidence that supports the calculation, not just final totals.
For service businesses, service-level accounting can be the hard part. If Microsoft asks for emissions tied to a service, project, contract, or reference unit, the supplier may need allocation logic that connects the company footprint to the relevant customer work in a reasonable and documented way.
How Keslio supports Microsoft suppliers
Keslio helps suppliers respond to customer sustainability requests with practical GHG calculation support, supporting documentation, and third-party consultant letters where the consultant-letter route applies. The work is service-led rather than software-led: Keslio starts with the request wording, then scopes the project around the response that is actually needed.
Keslio has supported a Singapore-based outsourced marketing services provider supplying Microsoft with annual GHG emissions calculations and consultant-letter reporting across three consecutive disclosure cycles. The work was accepted, and the client returned annually.
That experience shapes the way Keslio approaches Microsoft supplier GHG reporting support: first understand the request, then build the calculation, documentation, service-level accounting, and consultant-letter materials that fit the supplier's situation.
What Keslio can help with
- Reviewing the Microsoft supplier request.
- Confirming the likely reporting scope and response path.
- Preparing a data request checklist.
- Calculating Scope 1, Scope 2, and relevant Scope 3 emissions.
- Supporting service-level accounting for Microsoft requests unless the wording clearly indicates otherwise.
- Preparing methodology documentation.
- Preparing a third-party consultant letter where the consultant-letter route applies.
- Supporting one round of clarification.
- Preparing annual refreshes so the next cycle starts from a working base.
This work can also connect to broader supplier request support and GHG emissions calculations where the supplier needs help beyond the Microsoft-specific response.
What Keslio does not provide through this service
- Independent assurance unless separately arranged with an appropriate provider.
- Legal advice.
- Microsoft endorsement, approval, or partner status.
- Guaranteed acceptance by Microsoft.
- Broad ESG strategy unless separately scoped.
Keslio is not affiliated with, endorsed by, or approved by Microsoft. Keslio provides independent sustainability advisory and GHG reporting support for suppliers responding to customer requirements.
The first step is to review the request
For a supplier facing a Microsoft sustainability or GHG request, the fastest useful step is not to start calculating immediately. It is to understand the request wording, deadline, expected response path, and evidence requirements.
Once that is clear, the supplier can decide whether it needs a company-level GHG calculation, service-level accounting, methodology documentation, a consultant letter, an independent assurance path, or a broader support project.
Have a Microsoft supplier GHG request in front of you? Keslio can review the request wording for free and come back with the likely response path, data needs, timeline, and fixed-fee quote. Review your Microsoft supplier GHG request.
