DiplomaDPMAY +2.87%75 Operating Margin % is 19.66% as of Mar. 2026, which is 30% above its 10-year median of 15.13. GuruFocus rates DPMAY with a GF Score™ of 75/100 and a GF Value™ of $18.81 (Modestly Overvalued). The stock has 7 warning signs investors should review. Among 157 Industrial Distribution companies, Diploma ranks better than 96.82% on this metric.
Operating Margin % is calculated as Operating Income divided by its Revenue. Diploma's Operating Income for the
six
months ended in Mar. 2026 was $223 Mil. Diploma's Revenue for the
six
months ended in Mar. 2026 was $1,135 Mil. Therefore, Diploma's Operating Margin % for the quarter that ended in Mar. 2026 was 19.66%.
Good Sign:
Diploma PLC operating margin is expanding. Margin expansion is usually a good sign.
The historical rank and industry rank for Diploma's Operating Margin % or its related term are showing as below:
DPMAY'
s Operating Margin % Range Over the Past 10 Years
Min: 12.96 Med: 15.13 Max: 18.88
Current: 18.88
DPMAY's Operating Margin % is ranked better than 96.82% of 157
companies
in the Industrial Distribution industry
Industry Median: 4.74
vs DPMAY: 18.88
Diploma's 5-Year Average Operating Margin % Growth Rate was 6.90% per year.
Diploma's Operating Income for the
six
months ended in Mar. 2026 was $223 Mil.
Its Operating Income for the trailing twelve months (TTM) ended in Mar. 2026 was $417 Mil.
Just like Gross Margin %, it is important to see a company maintains its operating margin over time. Among the same industry, a company with higher operating margin is more efficient in its operation. It is also more stable during industry slowdown or recessions. Peter Lynch prefers those with higher margins than those with lower margins.
Be Aware
Operating Margin % can be manipulated by adjusting the rate of depreciation, depletion and amortization (DDA).
If a company is facing competition, its Operating Margin % may decline. Often the Operating Margin % declines well before the company's Revenue or even profit decline. Therefore, Operating Margin % is a very important indicator of whether the company is facing problems.
For instance, by 2012, Nokia (NOK)'s problems were well known and its stock had lost more than 90% of its market value since 2007. But Nokias Operating Margin % had already been in decline since 2002, although its Earnings per Share (Diluted) were still rising. Investors who paid attention to Operating Margin % would have avoided this huge loss. The same can be said for Research-in-Motion (RIMM).
Therefore, Operating Margin % is a very important screening filter for GuruFocus. GuruFocus's Buffett-Munger screener requires that the profit margin is either consistent or expanding. The Model Portfolio of the Buffett-Munger screener has outperformed the market every year since inception in 2009.
Diploma Operating Margin % Related Terms
Diploma Operating Margin % Historical Data
* Premium members only.
The historical data trend for Diploma's Operating Margin % can be seen below:
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
DPMAY vs GWW, FAST, FERG: Operating Margin % Comparison
For the Industrial Distribution subindustry, Diploma's Operating Margin %, along with its competitors' market caps and Operating Margin % data, can be viewed below:
* Competitive companies are chosen from companies within the same industry, with headquarter located in same country, with closest market capitalization; x-axis shows the market cap, and y-axis shows the term value; the bigger the dot, the larger the market cap. Note that "N/A" values will not show up in the chart.
Diploma Operating Margin % vs Industrial Distribution Industry
For the Industrial Distribution industry and Industrials sector, Diploma's Operating Margin % distribution charts can be found below:
* The bar in red indicates where Diploma's Operating Margin % falls into.
Operating Margin % - also known as operating income margin, operating profit margin and return on sales (ROS) - is the ratio of Operating Income divided by net sales or Revenue, usually presented in percent.
Diploma's Operating Margin % for the fiscal year that ended in Sep. 2025 is calculated as
* For Operating Data section: All numbers are indicated by the unit behind each term and all currency related amount are in USD. * For other sections: All numbers are in millions except for per share data, ratio, and percentage. All currency related amount are indicated in the company's associated stock exchange currency.
Diploma (DPMAY) has a Operating Margin % of 19.66% as of Mar. 2026. Operating margin is the ratio of total operating income to net sales. View historical data on Diploma and its competitors. This is 30% above median its historical median of 15.13. Over the past decade, Diploma's Operating Margin % has ranged from 12.96 to 18.88. According to the industry distribution chart, Diploma ranks #5 out of 157 companies in the Industrial Distribution industry, placing it in the top 3.2%.
Is Diploma's Operating Margin % too high?
Diploma's current Operating Margin % of 19.66% is 30% above median its 10-year median of 15.13. Over the past 10 years, this metric has ranged from a low of 12.96 to a high of 18.88. The Industrial Distribution industry median Operating Margin % is 4.74. Diploma's value of 19.66% is 314.8% above this industry median. Based on the distribution chart, Diploma ranks #5 out of 157 companies in the Industrial Distribution industry, which is in the top quartile — a strong position relative to peers. Overall, Diploma has a GF Score™ of 75/100 and is considered Modestly Overvalued, reflecting its overall financial health beyond just this single metric.
How does Diploma's Operating Margin % compare to GWW and FAST?
According to the Industrial Distribution industry distribution chart, Diploma ranks #5 out of 157 companies for Operating Margin %. This places Diploma in the top 3% of its industry — outperforming the majority of peers. The industry median Operating Margin % is 4.74. Diploma's value of 19.66% is 314.8% above this benchmark. Historically, Diploma's own Operating Margin % has ranged from 12.96 to 18.88 over the past decade. While the company's 10-year median is 15.13 vs. the industry median of 4.74, Diploma has consistently been above the industry average. See the competitive comparison table and distribution chart on this page for a detailed peer-by-peer breakdown.
What is a good Operating Margin % for an Industrial Distribution company?
The median Operating Margin % among Industrial Distribution companies is 4.74, based on 157 companies in the industry. Companies in the top quartile (top 25%) have a Operating Margin % significantly above this median, while those in the bottom quartile fall well below. However, Operating Margin % should not be evaluated in isolation — investors should consider it alongside profitability, growth, and financial strength metrics. Diploma's current Operating Margin % of 19.66% is 314.8% above the industry median. Use the industry distribution chart on this page to see where any company falls relative to its peers.
What does a high Operating Margin % mean?
A high Operating Margin % can signal that a stock is expensive relative to its fundamentals. Operating margin is the ratio of total operating income to net sales. View historical data on Diploma and its competitors. For the Industrial Distribution industry, the median Operating Margin % is 4.74 — values significantly above this may indicate overvaluation, while values below may suggest a bargain or underlying issues. Diploma's current Operating Margin % is 19.66%, which is 30% above median its own 10-year median of 15.13. However, context matters — high-growth companies often justify higher valuations. Always evaluate alongside other metrics like GF Score™ and GF Value™.
Is Diploma stock overvalued right now?
Based on GuruFocus' analysis, Diploma (DPMAY) is currently considered Modestly Overvalued. The stock's GF Value™ is $18.81, compared to a current price of $23.63 — trading 25.6% above its estimated fair value. The current Operating Margin % is 19.66%, which is 30% above median its 10-year median of 15.13 and 314.8% above the Industrial Distribution industry median of 4.74. Diploma's overall GF Score™ is 75/100 with 7 warning signs to review. Investors should evaluate multiple metrics — including profitability, growth, and financial strength — before making a decision.
How is Operating Margin % calculated?
Operating Margin % is calculated from a company's financial statements. For Diploma (DPMAY), the current Operating Margin % is 19.66% as of Mar. 2026. GuruFocus calculates this using data sourced from SEC filings and annual reports. See the calculation section and 30-year financial data on this page for the full breakdown.
Is Diploma (DPMAY) Overvalued in 2026?
Based on GuruFocus' analysis, Diploma stock appears to be overvalued.
The current stock price of $23.63 is trading 25.6% above its estimated GF Value™ of $18.81.
GuruFocus considers Diploma to be Modestly Overvalued.
Key valuation signals for DPMAY:
Operating Margin %: 19.66% (30% above median its 10-year median of 15.13)
GF Value™: $18.81 vs. price of $23.63 (25.6% above fair value)
Industry Position: 314.8% above the Industrial Distribution median (#5 of 157)
No single metric tells the full story. See the DPMAY stock analysis page for a complete view including 30-year financials, guru trades, and insider activity.
Diploma PLC is a group of businesses supplying specialised technical products and services to various industries. The Group is organized into three main reportable business sectors: Controls, Seals and Life Sciences. The company offers consumables, instrumentation, and related services to the healthcare and environmental industries; seals, gaskets, filters, cylinders, components, and kits for heavy mobile machinery and industrial equipment; and specialized wiring, connectors, fasteners, and control devices for various applications. It operates in segments such as Wire & Cable (UK), Industrial Automation, Specialty Adhesives, Windy City Wire, Interconnect and Specialty Fasteners. The company operates in UK, USA, Rest of Europe, and Rest of World.
75GF Score
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