An ESG questionnaire arrives with an implied condition: respond, or the relationship is at risk. The customer is asking for data you have never tracked, and admitting that feels like marking yourself for replacement.
The risk is real. It is also slower and more manageable than the questionnaire suggests. This guide sets out what customers are actually required to do with supplier data, when ESG does affect supplier selection, what a large customer expects from an SME, and how to protect the relationship while you build the capability.
| First question | Short answer |
|---|---|
| Will one incomplete response lose the customer? | Unlikely, if you respond, are honest about gaps, and give a timeline. |
| What does lose business? | Silence. Repeated non-response. Failing a stated minimum in a tender. |
| Are customers required to drop non-compliant suppliers? | No. CSRD requires them to make reasonable efforts to collect data and to document gaps, not to terminate suppliers. |
| What do they expect from a small supplier? | A response, honesty about what is tracked, accurate figures where given, and a direction of travel. |
| Can I push back on an unreasonable request? | Yes. The European Commission's 2025 SME guidance limits what large companies should demand of SME suppliers. |
The short answer
You are unlikely to lose an existing customer over one incomplete ESG response if you communicate professionally and show willingness to improve.
You may lose future opportunities if you consistently fail to engage while competitors build the capability.
The risk is gradual rather than immediate. It responds to ordinary effort.
What customers are required to do
Under CSRD, large companies report their Scope 3 emissions — the footprint of their value chain, including suppliers. To do so they need data from you. The regulation does not require them to drop suppliers who cannot provide complete data. It requires them to:
- Make reasonable efforts to collect supplier data
- Document their methodology and their data gaps
- Improve data quality over time
- Use estimates where measured data is not available
"Reasonable effort" means sending questionnaires, tracking responses, and following up. A partial response from you supports their compliance story. No response makes it harder to tell.
The regulatory pressure is toward engagement and improvement, not immediate completeness.
When ESG does affect supplier selection
Formal tender criteria. Some RFPs set minimum ESG conditions: an EcoVadis score above a threshold, or completion of the buyer's questionnaire as a condition of bidding. If you cannot meet a stated criterion you are ineligible, regardless of the relationship. If a minimum EcoVadis score is on the table, the free EcoVadis readiness check shows where you stand before you commit to an assessment.
Contract renewal. Procurement reviews supplier performance as a whole at renewal. ESG responsiveness is now part of that review. It is rarely decisive on its own; it contributes.
New supplier evaluation. Between two otherwise similar candidates, the one who can provide carbon data has an advantage.
Customer climate commitments. Customers with net-zero targets, science-based targets, or sustainability-linked financing have a strategic interest in suppliers who can support them. For those customers, supplier data is progress toward a public goal, not only compliance.
The actual risk: gradual marginalization
Sudden termination is rare. The pattern is slower.
They estimate instead of using your data. For their Scope 3 calculation they apply industry-average factors. Averages typically make a supplier look worse than its own figures would, which does not help a customer trying to show supply chain improvement. Even a basic measured figure from the free carbon calculator is better than being estimated.
They flag you as non-responsive. Procurement databases record supplier engagement. The flag shapes perception before it triggers action.
They look at alternatives. A customer under pressure to improve supply chain sustainability favors suppliers who make it easier. If a competitor provides what you do not, the comparison shifts — not this year, then eventually.
They exclude you from certain opportunities. High-profile projects, sustainability-led initiatives, and contracts with additional requirements go to suppliers who have shown the capability.
By the time the effect is visible, the pattern is established.
What customers expect from an SME supplier
Large customers know their supply chains include companies at every stage of ESG maturity. They do not expect a 30-person supplier to match a listed company. They expect:
A response. Acknowledge receipt. Engage with the questionnaire. Submit something by the deadline. Silence is worse than partial data.
Honesty about capability. If you do not track a metric, say so. If your policies are informal, describe them as informal. Transparency about limits is respected; inflated claims are not.
Accurate data where you provide it. Five defensible figures beat fifty questionable ones.
Direction. "We do not have Scope 3 data yet and plan to implement tracking next year" is a better answer than "No."
Professionalism. On time, in the format requested, with documents attached when asked.
None of this requires a sustainability team.
The European Commission's SME guidance
In 2025 the European Commission issued guidance intended to protect SME suppliers from disproportionate ESG data demands. Large companies are directed to limit questionnaires to what is necessary, not to require more from SMEs than the simplified VSME standard covers, and to allow reasonable timelines.
This gives you a basis for pushing back on an unreasonable request: "We want to support your sustainability reporting. Our understanding is that the VSME standard provides appropriate disclosure requirements for companies our size. Could we align our response to that framework?"
Protecting the relationship
Always respond. Half the questions answered shows engagement. No answer reads as concealment or indifference.
Communicate before the deadline. If you will miss it, say so first. If you have limits, explain them. The deadline guide has the wording.
Build in increments. Track energy this year. Add waste next year. Write a policy the year after. Steady improvement matters more than immediate completeness.
Record what you have done. Customers asking about your "sustainability journey" want to see movement. Keep a record of improvements, including small ones.
Ask what they actually need. Generic questionnaires ask for everything. Your customer may care about a few metrics. One conversation focuses the effort.
Where responsive suppliers gain
The same dynamics that create the risk create the opportunity. Suppliers fall into four groups: those who do not respond and are removing themselves from consideration; those who do the minimum and show it; those who complete the form adequately and treat it as administration; and a small group who use the request to demonstrate a well-run operation. Few suppliers are in the last group, and reaching it does not require a sustainability team. It requires four things.
Speed. Most suppliers take weeks; many miss the deadline. A supplier who responds in days — data tracked year-round, one owner, a system rather than a scramble — reads as a well-run company. Procurement carries that impression into everything else.
Data they can use without checking. Measurements rather than estimates where possible. A methodology note on any calculation. The policy uploaded, not "yes" ticked. Gaps stated with a date for closing them. Procurement teams consolidate hundreds of supplier responses; the ones they can use without follow-up become the ones they prefer.
Trajectory. Customers who track supplier ESG performance look at direction, not a single point. Activity data this year, calculated emissions next year, a target the year after. That pattern creates switching costs: there is little reason to move to an unproven supplier when the incumbent is visibly improving.
Being ahead of the request. If several customers use EcoVadis, get rated before the next one asks; the free EcoVadis readiness check shows what to fix first. If carbon requests are increasing, calculate Scope 1 and 2 now so the answer is a figure rather than a promise. Today's advanced capability is the standard expectation in two years.
Then use what you built. In proposals: your rating and the data you can provide on request. In tenders that score ESG: complete responses with documentation beat minimal compliance. In relationship conversations: "we achieved ISO 14001 last quarter; here is the certificate for your records." Inside the business, the same measurement usually finds money: energy efficiency cuts emissions and bills, waste reduction cuts disposal fees, safety improvements cut premiums and lost time. Present them as business improvements that also answer customer requirements.
The bottom line
You will probably not lose a customer over one incomplete questionnaire. You will be at an increasing disadvantage if you cannot engage with ESG requests at all, because the requests are not going to stop.
Respond. Be honest about capability. Improve each year. That is enough to protect most customer relationships while expectations settle.