Diploma Upgrades FY Outlook After "Very Strong" H1, Lifts Organic Growth to 6%–9% and Margins to 25%

Diploma upgraded full-year guidance after a "very strong" H1, raising organic growth to 6%–9%, acquisition-driven growth to 3% and operating margin to 22.5%–25%, which management says equates to roughly a 13% uplift to consensus operating profit and over 20% earnings growth.
Momentum is largely volume‑led and broad-based across Controls (not just Peerless), with growth excluding Peerless running at high single digits and strong contributions from IS Group, Clarendon and Windy.
Diploma has completed eight acquisitions for GBP 130 million and says the smaller "Diploma‑style" M&A pipeline is healthy; margins have benefitted from operating leverage and accretive deals but could moderate as future acquisitions may be lower‑margin.
Diploma (LON:DPLM) upgraded its full-year trading expectations during a conference call led by CEO Johnny Thomson, citing a "very strong" first half and confidence in momentum into the second half. Management raised organic growth guidance to 6%–9%, while leaving acquisition-driven growth expectations at 3%. The company also lifted its full-year operating margin outlook to 22.5%–25%, which Thomson said equates broadly to a 13% increase to consensus operating profit.
Thomson said the group's performance has been broad-based. While Peerless continues to stand out, he highlighted that growth excluding Peerless is running at "high single digits," which he said is well above the group's model.
Thomson attributed the upgrade to strength in the first half and sustained momentum. He added that, with the upgraded numbers, the company expects earnings to rise by over 20% this year, alongside "strong returns on capital."
Asked whether the organic growth upgrade reflects volume or pricing, CFO Wilson said Diploma's organic growth is "volume led." He gave Peerless as an example, noting that the business moderated prices on spot volumes, which helped generate additional volume intended to support a more sustainable long-term profile.
On the shape of growth through the year, Wilson said momentum seen in the first quarter continued into the second quarter. He reiterated earlier expectations that the second half would "mathematically moderate" due to tougher comparisons in the prior year, but said the overall shape remains similar with "everything being raised effectively."
Controls strength extends beyond Peerless
Thomson said Peerless continues to trade "very well," with sustainable positive market dynamics and market share gains. He expects the first half to be "incredibly strong" again, with some moderation in the second half against a strong comparator, but still landing "very good revenue and profit growth."
In response to questions about what is driving better-than-expected performance within Controls beyond Peerless, Thomson pointed to strength in several businesses, including:
IS Group, described as a large interconnect business with double-digit growth and "great margin progress," benefiting from exposure to energy transition, defense, and some aerospace across the U.S., the U.K., and Europe, along with market share gains.
Clarendon, a fasteners business with principal exposure to aerospace in Europe and the U.S., which has been growing at double digits for several years and continues to deliver strong organic growth. Thomson said Diploma has completed "a couple of small bolt-ons" to support Clarendon's growth.
Windy, which Thomson said is having a "great year," supported by exposure to data centers and distributed antenna systems and carrying good momentum into the second half.
Asked about Peerless and the broader market outlook, Thomson said demand remains "consistent and thriving," pointing to a large backlog of new builds and a significant refurbishment market. He added that supply chain constraints have not meaningfully changed and that management does not expect a shift in those constraints over a one-to-three-year view. Thomson emphasized that the Peerless performance is not only market-driven, citing market share gains and investment plans to expand opportunity in the U.S., increase exposure within the aerospace supply chain, and pursue defense and space opportunities as well as potential product expansion.
Seals and Life Sciences commentary
Thomson said Seals is running "fairly consistent" with last year. He noted North America is doing well, supported by infrastructure and "early progress in nuclear," while international performance—particularly R&G in the U.K.—has remained "pretty tough," holding sector growth for the first half broadly in line with the full year last year.
Life Sciences, he said, continues to deliver stable mid-single-digit growth despite a difficult healthcare backdrop. Thomson credited prior investments in management teams and business development capabilities, saying the company is "having to win quite a lot of market share" to stay in the mid-single-digit range. He cited market share gains in MedTech and "really good progress" in IVD in the U.K. and Ireland during the half. Management said investors should expect around 4%–6% growth for the half year.
Defense exposure, Middle East developments, and M&A pipeline
On defense, Thomson stressed that Diploma is highly diversified and that defense is only "a few percent" of group revenue, though he described it as a significant opportunity. He said the company has established expertise in defense, particularly in the U.K., and has been expanding capabilities more recently. Thomson noted investment behind "qualified expertise" led by David Goode, CEO of Controls, to access new market share opportunities.
Thomson also discussed steps taken to support European defense demand, including the opening of a new facility in the Czech Republic. He added that Diploma acquired a bolt-on business called Spring Solutions, which he described as principally defense-based in the U.K. with expansion into the U.S. and Europe.
Regarding the Middle East, Thomson said Diploma has no direct exposure there and minimal sourcing from the region. He said the company is monitoring supply chains, logistics, and potential pricing inflation tied to increased energy costs, but described any observed impact as "very, very patchy" so far. He added that Diploma believes it is well positioned to respond, referencing past ability to pass on prices through its customer service model.
On acquisitions, Thomson said the company completed eight acquisitions for a total spend of GBP 130 million in recent quarters, as referenced previously in January. He described the short-term pipeline as "very healthy," and said market conditions have been favorable for smaller, bilateral "Diploma style" deals. He also noted that larger M&A has been quieter over the last 12 to 18 months, with possible signs that activity may be easing.
On margins, Wilson said recent step-ups have been driven by operating leverage as the group scales and by margin-accretive acquisitions. Looking ahead, he said Peerless margins may moderate, and that future acquisitions could dilute margin because the company cannot expect to only buy businesses above 25% margin. He characterized the current margin level as "at the top end," while emphasizing expectations for continued growth in absolute profit.
About Diploma (LON:DPLM)
Diploma PLC, together with its subsidiaries, supplies specialized technical products and services in the United Kingdom, Continental Europe, North America, and internationally. It operates through three business sectors: Life Sciences, Seals, and Controls. The Life Sciences sector supplies technology-enabled products used in surgical procedures in operating theatres and endoscopy; testing equipment and services for clinical laboratories; and bio-pharma, food safety and testing, and other research-oriented products.