CDP Supply Chain Reporting: How It Works for Members and Suppliers

For many businesses, a CDP Supply Chain request is often their first real encounter with environmental disclosure. A large customer asks a supplier to report its emissions data through CDP by a set deadline. On the other side of that request sits a sustainability manager at the client, trying to collect comparable environmental data across hundreds or thousands of suppliers at once.

This article looks at CDP Supply Chain reporting from both ends: what the membership is, how the process works for the requesting company and for the supplier responding to it, the key dates in the 2026 cycle, and what makes a response effective. For a broader primer on CDP as a whole, Seedling's full CDP reporting guide covers the questionnaire, scoring and timeline in more detail.

What is CDP reporting, in brief?

CDP, formerly the Carbon Disclosure Project, runs the most widely used environmental disclosure system in the world. Companies complete a standardised questionnaire covering climate change and, where relevant, water security and forests, submit it through CDP's online portal, and receive a score from A down to D-. Disclosure is voluntary and not required by law in any jurisdiction, but it is increasingly requested by investors and large customers. Founded in 2000, CDP collected disclosures from more than 23,100 organisations in the 2025 cycle.

The Supply Chain programme is the part of CDP built specifically around the customer-to-supplier relationship.

What is CDP Supply Chain Membership?

CDP Supply Chain Membership is a programme that lets large buying organisations request environmental data from their suppliers through CDP, then access that data in a standardised, comparable format. CDP describes it as the world's largest environmental disclosure platform and supplier network.

The reason it exists is Scope 3. For most companies, the largest share of emissions sits not in their own operations but across their supply chain. CDP reports that corporate supply chain (Scope 3) emissions are, on average, 26 times greater than operational emissions (Scopes 1 and 2), yet many organisations have limited visibility of them. The programme closes that gap by gathering primary data directly from suppliers, rather than relying on industry averages.

Figures CDP publishes for the programme:

• Around 45,000 suppliers were requested to disclose through it in 2025.
• More than 270 corporate buyers are members, a group that includes Walmart, Microsoft and Nike.
• CDP reports around 18 years of experience running the programme.
• CDP also reports US$54.4bn in savings for companies cutting emissions across their value chains.

One point worth being clear on: membership sits with the buyer. Suppliers do not join or pay for membership. They respond to requests sent by members, and a supplier requested only by a Supply Chain member is also exempt from CDP's admin fee, covered further below. 

Why do companies use CDP to engage suppliers?

Several drivers sit behind supplier engagement through CDP:

• Better Scope 3 data. Primary supplier data produces a more accurate value-chain footprint than spend-based estimates alone.
• Risk and resilience. Environmental pressures in the supply chain, from extreme weather to resource constraints, translate into operational and financial risk for the buyer.
• Regulation. As mandatory climate disclosure expands, through the EU's Corporate Sustainability Reporting Directive and growing adoption of the ISSB's IFRS S2 standard across jurisdictions, buyers need better supplier data to meet their own obligations. 
• Standardisation. One questionnaire produces one comparable dataset, instead of dozens of bespoke supplier surveys in different formats.

How does the CDP Supply Chain work for the requesting company?

For the member, or buyer, the process runs roughly as follows:

1. Join as a member. The buyer selects a tier based on how many suppliers it wants to engage.
2. Request suppliers. The member nominates suppliers, who then receive a request to disclose through CDP.
3. Access the data. As suppliers respond, the member gains standardised data, scores and benchmarking through a dashboard, alongside support from a CDP account manager.
4. Act on it. The data feeds procurement decisions, the member's own Scope 3 inventory, supplier progress tracking, and prioritisation of where to focus engagement.

CDP offers three membership tiers, differentiated mainly by the number of supplier requests and the depth of data and support:

How does CDP Supply Chain work for the supplier?

When a member nominates a supplier, that supplier receives a request in the CDP portal. The steps for responding:

1. Receive the request. A Supply Chain request arrives with a direct link to the portal. Unlike a company disclosing voluntarily for the first time, a supplier requested by a customer does not need to complete the separate "register to disclose" step.
2. Accept or decline. Requests can be reviewed in the portal and accepted or declined. Disclosure is voluntary, so declining is possible, though it can affect the commercial relationship with the customer that asked.
3. Confirm the Submission Lead. This is the named contact who will submit the final response and acts as the key point of contact for CDP.
4. Confirm the admin fee position. A supplier requested only by a Supply Chain member is exempt from CDP's admin fee, so there is usually nothing to pay. The fee applies to companies that disclose independently as a Self-Selected Company, or that are also requested by investors through CDP's Capital Markets Signatories. 
5. Set up and complete the questionnaire. A short setup determines which questionnaire applies. Smaller companies may qualify for the streamlined SME questionnaire (1,000 or fewer employees and annual revenue of US$250m or less); larger companies complete the full corporate questionnaire.
6. Submit. Responses submitted by the scoring deadline are eligible for a CDP score, which is shared back with the requesting customer.

What are the key CDP dates for 2026?

CDP disclosure runs on an annual cycle. For the 2026 cycle:

• The response window is open now.
• 16 September 2026 is the scoring deadline. Responses submitted by this date are eligible for a score.
• The week commencing 26 October 2026 is the final response deadline, after which the questionnaire closes and no further edits are possible. Responses added between the scoring deadline and this date are accepted but not scored.
• Scores are released later in the cycle to the company and to the customers and investors who requested the data.

A supplier working towards a score, rather than simply submitting a response, should aim for the September deadline and start collecting data well before it, particularly where Scope 3 figures need gathering from its own suppliers.

What is the Supplier Engagement Assessment?

Worth knowing alongside the core disclosure: CDP also runs a Supplier Engagement Assessment, which scores companies on how effectively they engage their own suppliers on climate change, drawing on their CDP response. It is assessed from the full corporate questionnaire, so companies that respond through the SME version are not included. For a business that is both a supplier to larger customers and a buyer from its own suppliers, engaging that supply chain can improve its standing in this assessment as well as the quality of its Scope 3 data. It is a reminder that supply chain disclosure runs in both directions at once.

What are best practices for effective CDP supply chain reporting?

For a supplier responding to a request:

• Start with a full-scope footprint. A GHG Protocol-aligned inventory across Scopes 1, 2 and 3 is the foundation of any response. With that in place, much of the questionnaire becomes a matter of formatting data that already exists.
• Prioritise data quality. CDP scoring rewards complete, well-evidenced data. Activity-based data, such as actual energy use, distances travelled and weights of materials, gives a more accurate picture than spend-based estimates, and it reflects real reductions over time rather than just changes in spending. Spend-based data is a reasonable starting point, but a response built on activity data tends to score better and stays useful for longer.
• Explain any Scope 3 gaps. Where a category is excluded, CDP expects a stated reason rather than a silent omission. Seedling's Scope 3 guide covers the 15 categories in more detail.
• Reuse data across frameworks. CDP aligns with the GHG Protocol, IFRS S2, the ESRS behind CSRD, the SBTi and GRI, so a single robust inventory can support several reporting requirements at once.
• Consider verification. Third-party verification strengthens a response and is required at the top scoring bands of the full corporate questionnaire, though not for the SME version.
• Meet the scoring deadline. Submitting by 16 September is what makes a response eligible for a score, which is usually the part the requesting customer cares about most.

For a member engaging suppliers, response quality improves when suppliers are given time and clear guidance on what is being asked and why. Supplier maturity data and scorecards then help focus engagement on the suppliers that account for the largest share of Scope 3 emissions.

How can Seedling help with CDP supply chain reporting?

Whether a business is responding to a customer's CDP request or building the Scope 3 data to send requests of its own, the same foundation is needed: an accurate, full-scope carbon footprint.

Seedling pairs carbon accounting software with one-to-one support from a dedicated carbon expert. We help businesses measure a GHG Protocol-aligned footprint across Scopes 1, 2 and 3, using activity data wherever it improves accuracy, with accounting integrations and employee and supplier surveys that make the harder categories manageable. Our supplier engagement tool lets a business collect emissions data from its own suppliers, feeding straight into its footprint, which is useful for anyone building the Scope 3 picture that a CDP response or a Supply Chain membership relies on.

We also help set SBTi-aligned targets and build a quantified reduction plan, both of which feed into a stronger CDP score, and third-party verification is available through our ISO 14064 verification service. The result is the footprint, the plan and the evidence that a CDP response is built on.

Book a demo to see how the platform maps to the data CDP asks for.

Frequently asked questions

Is CDP Supply Chain reporting mandatory?‍

No. CDP disclosure is voluntary and not required by law in any jurisdiction. A supplier that receives a Supply Chain request can decline it, though declining can affect the relationship with the customer that asked.

Does a supplier have to pay to respond to a CDP request?‍

No, not usually. A supplier requested only by a Supply Chain member is exempt from CDP's admin fee. The fee applies to companies that disclose independently as a Self-Selected Company, or that are requested by investors through CDP's Capital Markets Signatories. Membership fees, separately, are paid by the buying organisations that request data, not by suppliers.

What is the difference between the SME and full corporate questionnaire?‍

The SME questionnaire is a shorter, climate-focused version available to companies with 1,000 or fewer employees and annual revenue of US$250m or less. Larger companies complete the full corporate questionnaire. 

When is the CDP scoring deadline in 2026?‍

16 September 2026. Responses submitted by then are eligible for a score. The final deadline for submitting unscored responses falls in the week commencing 26 October 2026.

‍