CDP supply chain questionnaire: answering a customer's CDP supplier request, and how supplier engagement is scored

A CDP supply chain request is a customer asking you to disclose your environmental data through CDP. You answer the same Full Corporate Questionnaire everyone else answers, plus an additional Supply Chain module for the customers who requested you. There is no legal obligation to respond, but non-response is recorded and visible to the company that asked. In 2025 roughly 45,000 suppliers were requested to disclose through the program, by more than 270 purchasing organizations.

Last updated August 2026. Most companies read a CDP supplier request as a courtesy item from a large customer's sustainability team. That misreads the situation in a way that costs you leverage. Your customer is not asking out of curiosity. Their own CDP score has a category worth 35% of a separate assessment that is driven entirely by whether they can show they engage suppliers like you, and they cannot score above a D on it unless they report that engagement. Understanding that changes both how seriously you should take the request and what you can ask for in return, such as time, a scope limited to what you can actually evidence, or help from their team.

What is the CDP supply chain program?

It is the mechanism large buyers use to collect environmental data from their own value chains through CDP rather than through bespoke spreadsheets. A purchasing organization joins as a Supply Chain member, submits a list of the suppliers it wants data from, and CDP sends those suppliers a request to disclose. CDP has run the program for 18 years and states that it has produced US$54.4bn in savings for companies cutting emissions across their value chains.

The reason it exists is arithmetic. For most companies Scope 3 is 70% to 90% of the total footprint, and the largest slice of Scope 3 is category 1, purchased goods and services. A buyer cannot improve that number by changing anything inside its own walls. It has to reach into its suppliers, which means it has to get data out of you first. That is the whole mechanism, and it is why the request keeps arriving every year rather than once.

What does the CDP supply chain questionnaire ask for that the main questionnaire does not?

Requested suppliers answer the standard Full Corporate Questionnaire, then a set of additional supply chain questions on top. The extra module is where you allocate emissions to the specific customer who requested you, describe collaboration opportunities with them, and report any emissions reductions attributable to work you did with that buyer. The main questionnaire covers your organization; the supply chain module covers your relationship with the requester.

One detail is worth knowing before you decide how much effort to put where. CDP's own 2026 scoring documentation states that information provided through the additional Supply Chain module is not evaluated in the Supplier Engagement Assessment. The module is for your customer's benefit, not your score. Your score comes from the main questionnaire, whose 13 modules are broken down on our CDP questionnaire page.

What are the CDP deadlines for a requested supplier in 2026?

CDP 2026 cycle dates that matter to a requested supplier

Milestone	When	What it means for you
Requesters finalize their supplier lists	Week of June 8	If you were added, you have already been notified. Late additions happen, and they compress your timeline
Response window opens	Week of June 15	The portal accepts responses. Nothing stops you drafting offline before this
Scoring deadline	16 September 2026	The date that actually matters. Submit after it and your response is published but not scored
Platform closes	Week of October 26	Final cutoff for unscored submissions and amendments

CDP's website gives the scoring deadline as 16 September while its guidance PDFs lay the cycle out by week and say "week of September 14". They are the same milestone, which is why third-party summaries disagree. Plan against September 16. The full working-backwards plan is in our CDP reporting deadline 2026 post.

Why is my customer pushing so hard for a CDP response?

Because their own assessment depends on it. CDP runs a Supplier Engagement Assessment, formerly the Supplier Engagement Rating, which grades purchasing organizations on how well they engage their supply chain on climate. It is scored from their answers to the main climate questionnaire, and supplier engagement is the single heaviest category in it. These are the published 2026 weightings, from CDP's Supplier Engagement Assessment Scoring Introduction 2026, version 1.0, published June 12 2026.

CDP Supplier Engagement Assessment 2026: scoring category weightings

Scoring category	Weighting
Supplier engagement	35%
Scope 3 emissions (including verification)	20%
Risk management processes	15%
Governance and business strategy	15%
Targets	15%

Two rules in that document explain the pressure you are feeling. First, to score above a D on the Supplier Engagement Assessment a company must report that it engages with suppliers at all, in question 5.11. Second, a fifth of the assessment sits in Scope 3 emissions and verification, and the quality of a buyer's Scope 3 number depends on how much real supplier data sits behind it rather than industry averages. Every supplier who does not respond pushes their number back toward estimates. To reach Leaderboard status a company must also respond publicly to a request from its own customers or capital markets, so the chain extends upward too.

This is useful to you. A request from a customer whose score depends on your cooperation is a negotiation, not a summons. Asking for a two-week extension, for the contact details of whoever runs their supplier program, or for confirmation of which categories they actually need, is normal and usually granted. Procurement teams already run something structurally identical when they collect and chase supplier documents, which is why the mature ones treat this like tracking certificates of insurance across a vendor list: a recurring compliance collection with owners and due dates, not an annual scramble.

The published 2026 Supplier Engagement Assessment bands

Final SEA score thresholds, 2026 (CDP sets these provisionally and may adjust them before scores are released)

Score	Threshold
A	76% to 100%
A-	66% to 75%
B	56% to 65%
B-	41% to 55%
C	26% to 40%
C-	16% to 25%
D	9% to 15%
D-	1% to 8%

Note that these are the assessment bands for the buyer, not your own CDP score. Those are a separate four-level system, explained in CDP scoring methodology 2026.

Do I have to respond to a CDP request from a customer?

No law requires it. CDP is a voluntary disclosure platform and nothing in it carries statutory force. What it carries is commercial force, and that has hardened. Large buyers increasingly write annual environmental disclosure into supplier codes of conduct and qualification criteria, which moves the request from a favor to a contract term. Once it is a contract term, the decision has been made somewhere above the sustainability team.

The realistic framing is that non-response is a recorded, visible answer rather than silence. Companies that are requested and do not respond appear as having declined to disclose, which is exactly the field a procurement team filters on when it builds a shortlist next cycle. If the contract matters, respond, even if the response is thin.

What happens if you do not respond to CDP?

A requested company that never submits is recorded as not having disclosed. A company that submits after the September scoring deadline is published but marked as not scored, which reads worse than it sounds, because a reader cannot tell a late filer from a bad one at a glance. There is no failing grade in the sense people expect: CDP does not issue an F to non-responders on the corporate score. The penalty is the absence of a score at all, next to competitors who have one.

A first response that answers every question honestly, including saying plainly that a Scope 3 category is estimated from spend or that no target is set yet, scores better than a polished response with blanks in the emissions module. Unanswered questions are scored zero, and CDP's methodology has "non-disclosure routes" where certain key data points are scored zero out of a denominator larger than the points that question was worth. Leaving a field blank can cost more than answering it imperfectly.

Can we answer the SME questionnaire instead?

Only if you qualify. A company with more than 1,000 employees or more than US$250 million in revenue must answer the full questionnaire. Below both of those thresholds you are eligible for the SME questionnaire, and you may still opt up to the full one. Organizations requested through RE100 are never SME-eligible.

There is a tradeoff worth understanding before you take the easier path. CDP's 2026 documentation states that companies disclosing through the SME questionnaire are not eligible to receive a Supplier Engagement Assessment. If your own suppliers matter to your story, or you eventually want to be recognized for engaging them, the SME route closes that door for the year. On the other side, 2026 is the first year SMEs are eligible for an A score on the corporate questionnaire, so the SME route is no longer a ceiling on recognition generally.

How do you prepare a first CDP supplier response in the time you have?

The failure mode is always data collection, not writing. Teams spend six weeks trying to get activity data out of suppliers and vendors, then rush the questionnaire in the last ten days. Invert that order.

1. Fix the boundary first, in writing. Decide operational control, financial control or equity share, list the entities inside it, and stop. Changing this later invalidates every number downstream. The choice is worked through in operational vs financial control.
2. Close Scope 1 and Scope 2 from bills. Fuel invoices, utility bills, meter readings and refrigerant records. This is bounded work with good data and it should be finished before Scope 3 starts. Note that CDP wants Scope 2 both ways, location-based and market-based, which is a difference from IFRS S2 and catches people out.
3. Screen all 15 Scope 3 categories from spend. Classify the accounts payable file and apply input-output factors. Every category gets a defensible number in days, you learn which two or three actually carry the footprint, and you can state honestly in the questionnaire that the figure is spend-derived. The method is in calculating Scope 3 from spend, and the accuracy tradeoff in spend-based vs activity-based.
4. Graduate only the material categories. Chasing supplier-specific data for a category worth 2% of your footprint is how the calendar disappears. Materiality is covered in Scope 3 materiality assessment.
5. Write the disclosures against the answers you have. Name your emission factor sources and your GWP version, say what is estimated, and say what is excluded and why. CDP rewards stated method far more than it rewards a suspiciously round number.
6. Answer the supply chain module last. It depends on your Scope 3 totals existing, and it is not scored in the Supplier Engagement Assessment anyway.

Step three is the one that changes the schedule, because it turns an open-ended supplier data project into a bounded classification job on records you already have. That is what our carbon accounting software is built to do: every ledger line gets a scope, a Scope 3 category, a confidence level and a link back to the invoice behind it, so a person reviews the uncertain tail instead of the whole file. You can run it on your own export in the demo above.

What should you do differently in year two?

The first response is about getting a complete, honest number submitted before a date. The second is about not repeating the work. Three things carry over if you build them now: an inventory management plan that records the boundary, methods, factor sources and GWP version so next year is a refresh rather than a rebuild; a fixed base year with a written recalculation policy, covered in how to set an emissions baseline year; and an evidence trail from each reported figure back to a source record, which is what an assurance provider samples when disclosure eventually stops being voluntary. For a US company that second thing is arriving on a schedule already, through California SB 253 and its assurance ladder.

If a customer request is your trigger, the tooling question is on CDP reporting software, and the wider US disclosure picture is on climate disclosure software.

CDP program facts here are taken from CDP's published 2026 materials, including the Supplier Engagement Assessment Scoring Introduction 2026 (version 1.0, June 12 2026) and CDP's supply chain and request-data pages, as available in August 2026. CDP sets score thresholds provisionally and reserves the right to adjust them before scores are released, and program dates can change, so confirm current requirements at cdp.net and in the guidance available through the CDP portal. Nothing here is legal or accounting advice.