My customer is asking for sustainability data – how to respond

More and more small companies are asked by their customers for climate and sustainability data. Usually it is because the customer has to report itself and needs data from its suppliers. With the EU's voluntary standard VS (formerly VSME) there is now a common format for the answer, and a limit on what the customer may require.

This guide explains how to respond without filling in a new form for every customer.

Why is the customer asking?

There are usually three reasons:

• The customer reports itself. Large companies have to disclose emissions and risks across their whole value chain, and your company is part of theirs.
• The customer manages risk. Banks and larger companies want to understand how their suppliers are affected by climate change and new requirements, whatever the law requires of them.
• Procurement. Sustainability information is increasingly a requirement or selection criterion when public or private buyers purchase.

The reason determines both what the customer needs and what it is entitled to require, so it pays to ask.

Step 1: Ask what the customer needs and why

Before you start calculating, find out:

• Which data the customer wants. Is it only climate emissions, or also energy, health and safety, and policies?
• For what purpose. Is it for the customer's own sustainability report, for risk assessment or for a procurement?
• For which period and in what format. Many customers are happy to receive a finished report under VS instead of their own form.
• Whether the figure should cover the whole company or only what you deliver to that customer.

Step 2: What may the customer require?

In VS, each data point is marked as required, required if applicable, voluntary or sector-specific. These markings are the basis of what is called the value chain cap: a limit on what a company with more than 1,000 employees may require, for reporting purposes, from a supplier with fewer than 1,000 employees.

• Required data may be requested by the customer.
• Required if applicable data may be requested when relevant, for example scope 3 emissions at a company where they are significant.
• Voluntary and sector-specific data may not be required for reporting purposes.

The cap differs for companies with fewer than ten employees and for companies with 10 to 999 employees; the smallest companies have to provide considerably less. According to the timetable known in autumn 2026, the cap applies from 1 January 2027, and how the rules would be transposed into Swedish law was not yet settled at that time.

The cap only applies to reporting. A customer can still ask for more for other purposes, for example to assess its own risks.

Should you say no?

Having the right to say no does not mean it is always wise. If the customer asks, it usually needs the data, and a good answer can be an advantage over competitors who cannot answer. Use the cap to keep the level reasonable, not to avoid answering.

Step 3: Get the figures from your bookkeeping

What customers ask for most often is climate data under B3 in VS: energy consumption and greenhouse gas emissions. Much of the data is already in your bookkeeping:

Quantities, such as litres or kilowatt-hours, give better figures than amounts of money. When only the amount is available, a spend-based calculation can be a reasonable start, especially for purchased goods and services, but say that the figure is an estimate.

For electricity, VS requires the location-based emissions figure. A market-based figure, which takes electricity contracts and guarantees of origin into account, may be added as voluntary information and should be labelled as such.

Step 4: Give the customer a figure it can use

A large customer will put your figure into its own calculation. A single total for your whole company is rarely enough. What makes the figure useful is:

• Emissions per service or product bought, so the customer can compare suppliers.
• How the figure is allocated, for example per amount invoiced, per delivery or per tonne-kilometre for transport.
• The period, so the customer knows which year the figure covers.
• Whether the figure is based on your own data or on default values.
• The trend over time, ideally several years, so the customer can see which way it is going.

For hauliers and other transport companies, tonne-kilometres are often a better measure than the number of deliveries or parcels, because that is how many customers calculate their own transport emissions.

Step 5: Be clear about what the figure is

• Write "data not available" instead of zero when you do not have the data. A zero means something did not happen.
• State the method and emission factors, and where they come from.
• Keep measured and estimated values apart.
• Do not promise too much. A report under VS is self-reported. If no one outside the company has reviewed it, avoid words such as "verified" or "audit-proof".
• Keep the source documents so every figure can be traced back to its invoice if the customer asks.

The short version

1. Ask what the customer needs, why and for which period.
2. Start from VS and check what the customer may require.
3. Calculate energy and emissions from your bookkeeping, preferably from quantities.
4. Allocate the figure so the customer can use it.
5. Be open about method, estimates and what is missing.

Washproof reads the bookkeeping from Fortnox or an SIE file, produces a report under VS and shows which invoice each figure is based on. If you want help from someone outside the company before the report goes to the customer, you can book advice from a senior sustainability advisor.

Sources

• Commission Recommendation (EU) 2025/1710 of 30 July 2025 on a voluntary sustainability reporting standard for small and medium-sized undertakings, OJ L 2025/1710.
• Commission Delegated Regulation C(2026) 5011 of 3 July 2026 (Voluntary Standard).