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Diploma sustainability score: 31/100

·Industrial Equipment / Machinery·Last verified 14 September 2026
31
out of 100
Below expectationsPending ReviewThin evidence· 6 src

Diploma scores 31/100 (Below expectations) on SINK's independent climate assessment — scored from public data only, no company payment can change a number. Last verified September 2026.

That places Diploma joint 467th of 680 companies scored, and joint 7th of 9 in Industrial Equipment / Machinery.

Diploma discloses Scope 1 and 2 emissions under mandatory UK listing rules but relies on intensity metrics rather than absolute reductions, masking revenue growth from acquisitions. Scope 3 data is stale (FY22, cost-based). No SBTi targets, no third-party verification, no renewable energy percentage disclosed. Clean controversies record.

Is this your company?

This score is built from public data only. If your practice is stronger than your disclosure, submit evidence for review — or challenge any question, free.

Evidence review — £99
The calculation

How is Diploma's SINK score calculated?

Same ten questions for every company. No private weighting.

SINK = (0.3 × Base + 0.7 × Performance) × Scale
Industry base impact
Industrial Equipment / Machinery sector ceiling.
44 / 100
Performance score
Sum of the 10 rubric questions, scored 0–10 each.
45 / 100
Raw score
Weighted average before scale penalty.
(0.3 × 44) + (0.7 × 45) = 44.7
Scale penalty
Multiplier based on absolute emissions volume — physics-first.
× 0.7
Final score
Rounded. Below expectations.
31 / 100
The ten questions

What is Diploma doing well, and where does it fall short?

Strongest on Controversies & Red Flags and Carbon Footprint — Operations (8/10, 6/10). Weakest on Targets & Commitments and Water Impact (3/10, 3/10).

Where the evidence comes from

What evidence is Diploma's score based on?

6 sources used in this assessment. All publicly available. Each row shows which rubric questions it informed.

Provisional evidence. Published on 7 sources and 3 independent parties — below our full-confidence threshold of 8 sources and 3 independent parties. Every source shown below passed the same quality checks as any other score: all live, none from data aggregators. There is simply less of it.

This company's public sustainability disclosure is limited. This score is based on the 6 verified sources cited below, rather than padded to a standard count.

This score is published on seven verified sources rather than the eight we require for full confidence. All seven are live and none comes from a data aggregator — there is simply less independent coverage of Diploma's environmental performance than of a larger listed company. One further source that genuinely evidences one of the ten questions would move this to full confidence. The score itself is unaffected by the count.

Limited data coverage. This assessment is based on 6 sources, 50% of which are self-reported by the company. Scores may change as independent evidence becomes available.

[1]Self-reported
Diploma 2024 Annual Report

5.7 Emissions intensity (Scope 1 & 2 tCO2e/£1m) FY23: 7.6

2024
Q1Q3Q9
View →
[2]Self-reported
Diploma Sustainability

38% reduction of Scope 1 and 2 emissions

Ongoing
Q1Q2Q3Q4Q5Q6Q7Q8Q9
View →
[3]Self-reported
Diploma Environment

Category 1: Purchased Goods and Services accounts for 51% of Scope 3 emissions

Ongoing
Q2Q4Q7
View →
[4]Public record
Diploma PLC — Wikipedia

Revenue: £1,524.5 million (2025)

Unknown
Q3Q10
View →
[5]Third-party verified
The State of Net Zero Greenwash

58% of almost 300 companies from the Forbes 2,000 found to be at risk of 'net zero greenwash'

Unknown
Q10
View →
[6]Third-party verified
SBTi Target Dashboard

The SBTi's Target Dashboard lists companies and financial institutions that have set science-based targets, or have committed to developing targets

Ongoing
Q8
View →

If you believe a source has been misread or a newer version exists, submit a challenge.

Diploma in context

How does Diploma compare with other industrial equipment / machinery companies?

Diploma is tied at the bottom of the industrial equipment / machinery pack.

Among the 9 major industrial equipment / machinery brands we've scored, Diploma is tied =7th of 9, with 2 others.

=7/9
Diploma's rank
38
Industry average
31
Industry low
48
Industry high
How this score has moved

Has Diploma's score changed?

today

Score history begins .

As Diploma's score updates, the trajectory will appear here.

We're backfilling historical scores for FTSE 100 and S&P 100 companies over the coming weeks.

What's being contested

Has Diploma's score been challenged?

This score is not currently being contested.

Every challenge is published. We'd rather be corrected than wrong — that's the whole point.

No challenges submitted yet. If you have evidence that contradicts this score, you can challenge any question above — cite a public source and we'll review it.

About Diploma

Diploma is a UK-listed specialty distributor of technical products including seals, cables, wiring, and life science equipment across Europe and North America. Mid-cap industrial business with 1,500+ employees, £1.5bn FY2025 revenue, grown primarily through acquisition. Low direct environmental footprint; supply chain exposure through procurement.

Founded
Headquarters
GB
Employees
~3,390
Annual revenue
~£1,524M
Company website ↗
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