Diploma PLC (DPLM) — Company Research

Last updated: 12 May 2026. All financial figures sourced from Diploma PLC RNS announcements and annual reports.

Diploma PLC (LSE: DPLM) is a FTSE 100 specialty distribution group headquartered in London. The company supplies highly specialised technical products and services across three sectors — Controls, Seals and Life Sciences — to industrial, healthcare and scientific customers primarily in the US, Canada, the UK, Europe and Australia. Diploma has compounded adjusted earnings per share at an average of approximately 18% per year over the last seven years through a combination of volume-led organic growth and bolt-on acquisitions, building a track record that the company describes as "sustainable quality compounding." The most recent completed financial year, FY2025 (ended 30 September 2025), saw revenue reach £1,524.5m with 11% organic growth — ahead of expectations — and adjusted EPS rising 21% to 176.0p. A significant upgrade to FY2026 guidance was issued in March 2026, lifting the organic growth outlook to 9% and the operating margin forecast to approximately 25%. The half-year results for H1 FY2026 (six months ended 31 March 2026) are scheduled for release on 19 May 2026.

1. Company Snapshot

Item	Detail
Full name	Diploma PLC
Ticker / exchange	DPLM — London Stock Exchange (LSE)
Index membership	FTSE 100
Sector	Industrials — Specialty Distribution & Value-Add Solutions
Headquarters	10–11 Charterhouse Square, London EC1M 6EE
Founded	1931 (listed on LSE; Diploma name since 1977)
Financial year end	30 September
Most recent completed FY	FY2025 (year ended 30 September 2025)
FY2025 revenue	£1,524.5m
FY2025 adj. operating profit	£342.7m
FY2025 adj. operating margin	22.5%
FY2025 adj. EPS (diluted)	176.0p
FY2025 full-year dividend	62.3p (interim 18.2p + final 44.1p)
FY2025 free cash flow	£247.2m
Net debt / EBITDA (FY2025 YE)	0.8x
Share price (approx. May 2026)	~6,915p
Market capitalisation (approx.)	~£9.3bn
Employees (approx.)	~3,400
Chief Executive	Johnny Thomson (since February 2019)
Chief Financial Officer	Wilson Ng (appointed August 2025)
Registrar	Equiniti Limited

2. Bull Case vs Bear Case

Distilled from the full report below — factual only, no ratings.

Bull Case

• Consistent EPS compounding: Diploma has grown adjusted EPS at an average of approximately 18% per annum over the last seven years, including a 21% increase in FY2025 to 176.0p and guidance for over 20% earnings growth in FY2026.
• Margin expansion runway: Adjusted operating margin reached 22.5% in FY2025, up 160 basis points year-on-year. The March 2026 trading update upgraded the FY2026 margin target to approximately 25%, representing a significant step-up.
• Volume-led organic growth: FY2025 organic revenue growth of 11% was volume-led across all three sectors; Q1 FY2026 delivered 14% organic growth, and H1 FY2026 guidance was raised to 9% for the full year.
• Active acquisition pipeline at disciplined multiples: Diploma completed seven acquisitions in FY2025 and eight in the two quarters to January 2026 for c.£130m at average multiples of approximately 6–8x EBIT, in structurally growing markets including aerospace, defence and in vitro diagnostics.
• Low financial leverage: Net debt/EBITDA was 0.8x at FY2025 year-end, providing significant balance sheet capacity for further M&A while maintaining investment-grade characteristics.
• Aerospace and defence tailwind: Peerless Aerospace Fasteners, acquired in FY2024, has significantly exceeded expectations and benefits from favourable long-cycle aerospace demand and supply dynamics.
• Diversified geography and end markets: Revenues span the US, Canada, UK, Europe and Australia, reducing single-market concentration, with exposure to structural growth markets including datacentres, digital antenna systems, nuclear power and medtech.

Bear Case

• Premium valuation: With a share price of approximately 6,915p and a P/E ratio of approximately 50x on trailing earnings, the stock is priced for continued execution. Any guidance miss or margin disappointment could lead to a material de-rating.
• Peerless concentration risk: A significant portion of the FY2026 growth and margin upgrade is attributed to Peerless. Management has guided that Peerless H2 FY2026 growth will return to "more typical growth rates" against very strong comparators, creating a high-comparator headwind in the second half.
• International Seals weakness: International Seals — particularly in the UK — has remained challenging, with the segment delivering only 2% organic growth in FY2025. UK industrial demand has not recovered.
• Acquisition integration risk: Diploma completed 15 acquisitions across FY2025 and the first half of FY2026. Integrating a large number of businesses simultaneously across multiple geographies carries execution risk.
• Currency headwinds: A significant proportion of revenue is earned in US dollars, Canadian dollars and Euros. A strengthening pound could reduce reported sterling revenues and profits. FX was a headwind to reported growth in Q1 FY2026 of approximately 2%.
• US tariff and trade policy uncertainty: A material portion of Diploma's revenue originates in or is distributed through the United States. Escalating US tariffs on goods and components could raise input costs across the Controls and Seals businesses.
• Small CFO tenure: Wilson Ng was appointed Acting CFO only in August 2025. While he brings relevant experience from within the business, the relative newness of the CFO appointment coincides with an accelerated growth phase.

3. What Does This Company Actually Do?

Diploma PLC is a value-add solutions group, not a commodity distributor. The company does not simply take margin by moving product from manufacturer to customer; instead, it embeds itself in the supply chains of specialised customers by providing technical expertise, customisation, inventory management, kitting, subassembly and rapid fulfilment of highly critical low-volume, high-complexity parts. The products Diploma supplies are typically low-cost relative to the total cost of a customer's operation but are critical to that operation — a seal that prevents hydraulic failure, a connector cable in a data centre, or a diagnostic reagent in a hospital laboratory. This criticality gives Diploma pricing power and strong customer retention.

The business operates across three sectors:

Sector	Approx. % of FY2025 revenue	What it does
Controls	~48%	Supplies specialised wiring, cable, connectors and related products to original equipment manufacturers and the construction market. Key businesses include Windy City Wire (US cable distributor serving datacentres, commercial construction and digital antenna systems), Clarendon Specialty Fasteners (aerospace fasteners, expanded via acquisition of Peerless and Swift Aerospace), and IS Group / international controls businesses serving defence, energy and electronics markets.
Seals	~36%	Supplies sealing solutions, fluid power products and related components for industrial, mobile and off-highway applications. North American Seals serves infrastructure and, increasingly, nuclear power generation. International Seals operates across the UK and Europe, serving hydraulics, industrial machinery and mobile equipment markets.
Life Sciences	~16%	Supplies laboratory instrumentation, consumables, reagents, surgical equipment and diagnostic products to hospitals, clinical laboratories and research institutions in Canada, Australia and Europe. The business has driven share gains in medtech and in vitro diagnostics (IVD).

Diploma operates a decentralised model: acquired businesses are run autonomously by their management teams with central support for strategy, capital allocation, finance, HR and M&A. The group primarily operates in the US (~50% of revenue), the UK, Canada, Europe and Australia.

4. The Business Model

Value-add distribution, not commodity distribution. Diploma's businesses compete on technical expertise, product breadth, customisation (kitting, subassembly), rapid delivery and embedded customer relationships — not on price alone. This positions them against general distributors and gives them the ability to charge a premium for a genuinely critical service.

Critical products, low substitution risk. The products Diploma distributes are typically low-cost as a proportion of a customer's total project or operating budget, but high-consequence if unavailable or of poor quality. This makes customers reluctant to switch for marginal price savings, supporting retention rates and repeat business.

Decentralised, entrepreneur-friendly acquisition model. Diploma acquires founder-led or family-owned businesses, retaining the original management team and culture. The group provides central capital, M&A capability, HR support and strategic guidance without imposing heavy corporate overhead. This approach helps preserve the relationships and agility that made the acquired business valuable in the first place.

Disciplined M&A at sensible multiples. Diploma targets acquisitions at approximately 6–8x EBIT, well below the multiples at which the group's own shares trade. This creates value for shareholders as acquired earnings are capitalised at the group's higher multiple on announcement. Post-acquisition margin improvement is a further source of value creation.

Organic growth engine. The group targets mid-single-digit organic revenue growth through its financial model, underpinned by market share gains, new product introductions and expansion into adjacent end markets. FY2025 organic growth of 11% significantly exceeded this model rate.

Recurring, mission-critical revenue base. A substantial portion of revenue comes from consumable products and replacement parts that are reordered repeatedly. This provides resilience relative to project-based or one-time sales models.

5. Financial Health

Fiscal Year	Revenue (£m)	YoY %	GAAP EPS diluted (p)	Adjusted EPS	Dividend/share (p)	Net debt at YE
FY2025 (yr ended 30 Sep 2025)	£1,524.5m	+12%	—	176.0p	62.3p	£299.4m
FY2024 (yr ended 30 Sep 2024)	~£1,363m	+14%	—	145.8p	59.3p	£419.6m
FY2023 (yr ended 30 Sep 2023)	~£1,197m	~+5%	—	~120p	56.5p	£254.7m
FY2022 (yr ended 30 Sep 2022)	~£1,140m	~+37%	—	~97p	52.5p	£328.9m
FY2021 (yr ended 30 Sep 2021)	~£831m	~+17%	—	~79p	42.0p	£181.4m

Note: GAAP (statutory) diluted EPS figures are not separately published in the readily available preliminary announcements — Diploma reports adjusted EPS as its primary per-share measure. FY2025 revenue of £1,524.5m and adj EPS of 176.0p are from the official 18 November 2025 RNS. FY2024 adj EPS of 145.8p is from the 19 November 2024 RNS. Earlier years are estimates based on reported organic and acquisition growth rates from official RNS filings; treat as approximate. Net debt expressed as a leverage multiple where only FY2025 is confirmed (0.8x EBITDA).

Half-year / quarterly periods (most recent first):

Period	Revenue / update	Organic growth	Key note
H1 FY2026 (6m to 31 Mar 2026) — results due 19 May 2026	Not yet published	Not yet published	March 2026 trading update guided FY2026 organic growth of 9% (H1-weighted) and operating margin of c.25%. Q1 FY2026 organic growth was 14%.
Q1 FY2026 trading update (14 Jan 2026)	Not reported as revenue	+14%	4 acquisitions completed for c.£75m. FY guidance maintained at 6% organic, 22.5% margin at that point.
H2 FY2025 (6m to 30 Sep 2025)	Implied ~£820m	Implied strong	Full-year FY2025 organic growth of 11% driven by very strong H2; Controls +20% organic for the full year.
H1 FY2025 (6m to 31 Mar 2025) — reported 20 May 2025	Partial year	Part of 11% FY	Interim dividend 18.2p announced. Life Sciences +6%, Controls strong double-digit, Seals recovering.

6. Valuation & Market Data

Raw metrics, May 2026. Not opinions on whether the stock is cheap or expensive.

Metric	Value
Share price (approx. May 2026)	~6,915p
Market capitalisation (approx.)	~£9.3bn
52-week range (approx.)	~5,500p – ~7,000p
Trailing P/E (GAAP)	~50x
FY2025 adj. EPS	176.0p
FY2025 full-year dividend per share	62.3p
Dividend yield (approx.)	~0.9%
FY2025 revenue	£1,524.5m
Price/Sales (approx.)	~6.1x
FY2025 adj. operating margin	22.5%
FY2026 operating margin guidance (upgraded Mar 2026)	~25%
Net debt / EBITDA (FY2025 YE)	0.8x
Return on capital employed (FY2025)	20.9% (adjusted, up 180bps YoY)
FY2025 free cash flow	£247.2m
Shares in issue (approx.)	~134.5m
Index	FTSE 100

7. What Are They Building / What's Coming?

Accelerated M&A in aerospace and defence. Diploma has deliberately shifted its acquisition mix towards higher-growth, higher-margin end markets. The acquisition of Peerless Aerospace Fasteners in March 2024 and the subsequent acquisition of Swift Aerospace (completed into Clarendon Specialty Fasteners, announced Q1 FY2026) have extended the group's presence in aerospace fastener distribution across North America and Europe. Management has described aerospace demand and supply characteristics as "favourable and sustainable." The group completed eight acquisitions in the two quarters to January 2026 for approximately £130m total consideration, adding an estimated £20m of annualised operating profit.

Operating margin expansion target. The group's original FY2026 guidance issued in November 2025 targeted approximately 22.5% operating margin. This was significantly upgraded in the March 2026 trading update to approximately 25%, driven by accretive contribution from Peerless and steady margin accretion across the broader portfolio. Management has stated this upgrade represents approximately a 13% uplift to consensus operating profit for FY2026.

Geographic expansion in Controls. IS Group and Clarendon continue to grow in structurally expanding markets including energy, defence and aerospace internationally. Windy City Wire is growing strongly in the US, with datacentres and digital antenna systems cited as particular growth vectors.

Nuclear power generation — an emerging opportunity. North American Seals has been highlighted by management as beginning to develop exposure to nuclear power generation, which management has described as an "exciting development." Nuclear represents a long-cycle, high-criticality market that is well-suited to Diploma's value-add distribution model.

Life Sciences IVD expansion. The Life Sciences sector has been growing through share gains in in vitro diagnostics (IVD) markets in Canada and Australia. The group targets continued penetration of the diagnostics market, which has structural growth driven by ageing populations and increased disease screening.

Bolt-on acquisition pipeline remains active. Management described the short-term acquisition pipeline as healthy as of the March 2026 trading update, with an expectation that further deals will be completed. Potential acquisitions are not included in guidance, meaning there is scope for guidance upgrades if deals complete.

8. Competitive Landscape

Diploma operates in a fragmented specialty distribution market. It does not compete primarily with commodity distributors but with other value-add specialists and, in some areas, with direct supply by manufacturers. The key competitive distinction is depth of technical expertise, speed of supply, breadth of product range for specialised applications, and the ability to provide kitting and subassembly services. The closest publicly traded peers are other specialty distribution groups, though none operates an identical sector footprint to Diploma.

Peer	Market cap (approx. May 2026)	Notable KPI
Bunzl PLC (LON: BNZL)	~£7.2bn	Revenue ~£12bn+; FTSE 100 distributor of non-food consumables
IMCD N.V. (AMS: IMCD)	~£5.0bn	Speciality chemicals distributor; revenue ~€4.2bn
Roper Technologies (Nasdaq: ROP)	~£28bn	Diversified industrial technology; strong free cash flow
Spirent / Halma (LON: HLMA)	Halma ~£9.0bn	Halma: safety, environment, medical equipment; adj. EPS growth target 5%+ pa

In each of its three sectors, Diploma also competes with sector-specific distributors and direct-to-customer programmes from manufacturers. In Seals, US competitors include Parker Hannifin's distribution arm and regional seal distributors. In Controls, competitors in the cable and wire space include Anixter (Wesco International) and regional electrical distributors. In Life Sciences, the group competes with Fisher Scientific (Thermo Fisher) distribution channels and regional medical device distributors. Diploma's advantage in each case is its depth of specialisation and embedded customer service rather than scale.

9. Leadership and Ownership

Johnny Thomson — Chief Executive Officer (joined February 2019). Thomson has been the architect of Diploma's accelerated growth strategy. Before joining Diploma he was Group CFO at Compass Group PLC and held a regional managing director role in Latin America at Compass. He also holds a non-executive advisory role at TDR Capital LLP.

Wilson Ng — Chief Financial Officer (appointed Acting CFO August 2025, confirmed CFO). Ng joined Diploma in 2022 as Group Financial Controller. He previously served as a divisional Finance Director at Spirax Group plc and held senior roles at GKN plc. He is an ICAEW chartered accountant.

David Lowden — Board Chair (joined October 2021). Former Chief Executive of Taylor Nelson Sofres; currently also Chair of Capita PLC and Senior Independent Director at Morgan Sindall plc.

Katie Bickerstaffe — Senior Independent Director (joined October 2024). Former Co-CEO at Marks & Spencer Group plc.

Anna Lawrence — Group General Counsel & Company Secretary (joined May 2025). Former Group General Counsel at Elementis plc; trained at Allen & Overy.

Sector leadership: David Goode (CEO, Controls Sector), Neil Yazdani (CEO, North American Seals Sector, from April 2025), Peter Soelberg (CEO, Life Sciences Sector).

Institutional ownership: Institutional investors hold approximately 87% of Diploma's shares. Capital Research and Management Company is the largest disclosed shareholder at approximately 13% of shares outstanding. FMR LLC (Fidelity) disclosed a 5.27% voting interest as of April 2025. The top 12 shareholders collectively hold approximately 52% of shares. Insider ownership is under 1%. The shareholder base includes long-only global and UK asset managers, pension funds and a growing proportion of passive/index investors (FTSE 100 trackers and global ETFs).

Director / Person	Role	Shares held (approx.)	Transactions (recent)	Date	Price	Source
Johnny Thomson	CEO	—	LTIP / performance share awards	Various 2025	N/A (award)	Diploma RNS
Wilson Ng	CFO	—	Appointed August 2025	Aug 2025	—	Diploma RNS
David Lowden	Chair	—	—	—	—	—
Capital Research & Mgmt	Institutional shareholder	~13% of shares	Largest disclosed holder	—	—	Public disclosure
FMR LLC (Fidelity)	Institutional shareholder	~5.27%	Disclosed April 2025	Apr 2025	—	Public disclosure

10. Risks and Challenges

• Valuation and earnings expectations (Market Risk): At approximately 50x trailing P/E, the share price embeds expectations of continued above-market earnings growth. Any material shortfall to guidance — particularly given the significant margin upgrade for FY2026 — could result in a disproportionate share price decline.
• Peerless comparator risk (Operational): The FY2026 guidance upgrade is substantially driven by Peerless Aerospace Fasteners. Management has explicitly guided that H2 FY2026 growth at Peerless will return to "more typical growth rates" against very strong H2 FY2025 comparators, which could lead to a slower second half.
• International Seals weakness (Operational): International Seals, particularly UK operations, has remained challenging since FY2024. A prolonged weakness in UK and European industrial demand would suppress this segment's contribution and dampen overall group organic growth.
• Acquisition integration (Execution Risk): Diploma completed approximately 15 acquisitions across FY2025 and the first half of FY2026. Running a large number of integrations simultaneously, across multiple geographies and sectors, raises the risk of management distraction, cultural misalignment or failure to realise expected synergies.
• Currency exposure (FX Risk): Approximately half of revenue is earned outside the UK, predominantly in US dollars and Canadian dollars. A significant strengthening of sterling against these currencies would reduce reported revenue, profit and EPS even if underlying performance is unchanged. FX was a 2% headwind to reported growth in Q1 FY2026.
• US trade policy and tariffs (Macro / Geopolitical Risk): A material portion of Diploma's business — particularly Controls (Windy City Wire, Peerless, Clarendon) and North American Seals — operates in the United States. Escalating US tariffs on imported goods and components could raise input costs and create supply chain disruption. The aerospace fasteners business, in particular, is dependent on an internationally sourced supply chain.
• Healthcare funding pressure (Sector Risk): Life Sciences is subject to government healthcare budget constraints in Canada, Australia and Europe. Slower hospital procurement or reduced diagnostics spend would affect the segment's organic growth.
• Key person dependency (Governance Risk): Johnny Thomson's tenure and track record of M&A execution and culture-building are central to the group's investment case. Any CEO transition or extended absence would represent an uncertainty event.
• Debt capacity constraints (Financial Risk): While leverage is modest at 0.8x EBITDA, a sustained period of large acquisitions without earnings growth catch-up could increase leverage and potentially restrict financial flexibility.

11. Recent Developments

• 18 March 2026 — Significant FY2026 guidance upgrade. — Diploma issued a trading update upgrading its FY2026 full-year guidance. Organic revenue growth guidance was raised from 6% to 9% (remaining H1-weighted). Operating margin guidance was upgraded from approximately 22.5% to approximately 25%. This represented an approximately 13% uplift to consensus adjusted operating profit of £377m (as at 17 March 2026). Management stated it expects "another year of sustainable quality compounding, with earnings growth over 20% at strong returns on capital." Net acquisition growth guidance was maintained at approximately 3%, with eight acquisitions completed in the two preceding quarters for approximately £130m total consideration, contributing approximately £20m of annualised operating profit.
• 14 January 2026 — Q1 FY2026 trading update and acquisitions. — Diploma reported 14% organic revenue growth in Q1 FY2026 (the three months to 31 December 2025). The company completed four acquisitions in the quarter for approximately £75m, including Swift Aerospace, which extended Clarendon Specialty Fasteners' reach in aerospace fastener distribution into Europe. FY2026 full-year guidance at that point was maintained at 6% organic growth and 22.5% margin. Net acquisition growth was upgraded from 2% to 3%.
• 31 January 2026 — Handbook of Diploma Businesses published. — Diploma published an updated Handbook of Diploma Businesses, providing detailed profiles of the group's individual operating businesses across all three sectors.
• 18 November 2025 — FY2025 full-year preliminary results. — Diploma reported "very strong results, ahead of expectations" for the year ended 30 September 2025. Revenue of £1,524.5m represented +12% reported and +11% organic growth. Adjusted operating profit rose 20% to £342.7m, with margin up 160 basis points to 22.5%. Adjusted EPS grew 21% to 176.0p. The board recommended a final dividend of 44.1p (full-year 62.3p, up 5%). Return on capital employed was 20.9%, up 180 basis points. Free cash flow grew 25% to £247.2m. By sector: Controls +20% organic, Life Sciences +6% organic, Seals +2% organic. Seven acquisitions were completed during FY2025 in aerospace, defence and IVD markets. Initial FY2026 guidance was set at 6% organic growth, H1-weighted, and 22.5% margin — subsequently significantly upgraded in March 2026.
• 27 March 2024 — Acquisition of Peerless Aerospace Fasteners. — Diploma completed the acquisition of Peerless Aerospace Fasteners, a distributor of aerospace-grade fasteners based in the United States. Peerless has since materially exceeded management expectations in FY2025 and H1 FY2026, becoming a major growth driver for the Controls sector.

12. Key Dates Coming Up

• 19 May 2026 — Half Year Results for the six months ended 31 March 2026 (H1 FY2026) — scheduled announcement. Interim dividend will also be announced on this date.
• 16 Jul 2026 — Q3 FY2026 Trading Update.
• 17 Nov 2026 — Preliminary Full Year Results for FY2026 (year ended 30 September 2026). Final dividend announcement.
• 04 Dec 2026 — Annual Report and Accounts FY2026 posted to shareholders.
• 13 Jan 2027 — Annual General Meeting (2027).

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