MIR Q4 Deep Dive: Nuclear Power Growth and Acquisitions Offset Margin Pressures

Radiation safety company Mirion (NYSE:MIR) missed Wall Street’s revenue expectations in Q4 CY2025, but sales rose 9.1% year on year to $277.4 million. Its non-GAAP profit of $0.15 per share was 7.8% below analysts’ consensus estimates.

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StockStory’s Take

Mirion’s fourth-quarter results were met with a negative market reaction, reflecting missed revenue and non-GAAP EPS expectations. Management attributed the softer top-line to challenging comparisons in its labs and research and RTQA (Radiation Therapy Quality Assurance) segments, as well as delays in government-related orders due to a prolonged shutdown. CEO Thomas Logan explained that strong order growth in nuclear power and nuclear medicine helped offset these headwinds, with Logan noting, “We booked record orders in 2025 totaling more than $1 billion, largely driven by the nuclear power market.”

Looking forward, Mirion’s guidance for the coming year is shaped by anticipated double-digit growth in nuclear power and nuclear medicine, as well as the integration of recent acquisitions. However, management acknowledged headwinds from margin dilution related to the Paragon deal and ongoing tariff pressures. CFO Brian Schopfer stated that “adjusted EBITDA margins are expected to expand 90 basis points,” but cautioned that the first quarter will be the lightest due to seasonality and Paragon’s impact. The company is emphasizing operational leverage, procurement savings, and AI-driven productivity as paths to margin improvement.

Key Insights from Management’s Remarks

Management cited robust demand in nuclear power and nuclear medicine, supported by recent acquisitions, as key drivers of order growth. However, segment-specific challenges and acquisition integration weighed on margins and overall performance.

• Nuclear power momentum: Orders in the nuclear power segment surged, driven by both organic demand and large project wins. Management highlighted that approximately 80% of revenue comes from the existing operating fleet, with CEO Thomas Logan stating, “We cover the breadth of the century-long cradle-to-grave lifespan of a modern large-scale reactor.”
• Acquisition-driven expansion: The acquisitions of CertRec and Paragon expanded Mirion’s North American nuclear power exposure, now accounting for roughly 40% of total revenue. These moves also positioned Mirion for greater involvement in emerging small modular reactor (SMR) projects.
• Medical segment headwinds: The medical segment faced tough year-over-year comparisons and macroeconomic headwinds, especially in RTQA and dosimetry. Despite this, management expects a rebound as hardware sales recover and new product launches gain traction.
• Operational improvements: Procurement initiatives and cost savings contributed to margin improvement, with nearly 100 basis points of adjusted EBITDA margin gain in 2025 from procurement alone. Still, the Paragon acquisition was margin dilutive in the short term.
• AI and digital initiatives: Mirion launched 17 internal AI applications aimed at productivity, and recently appointed its first Chief AI and Digital Officer. The company sees long-term potential for AI to improve both customer-facing offerings and internal efficiency.

Drivers of Future Performance

Mirion’s outlook for the next year is anchored by large project execution in nuclear power, ongoing acquisition integration, and rising demand in nuclear medicine, but tempered by margin headwinds and investment in AI.

• Nuclear power project pipeline: Management expects continued double-digit growth in the nuclear power segment, supported by over $400 million in large opportunity projects for the year, including significant SMR (small modular reactor) activity. However, timing for these large projects remains unpredictable, which could impact quarterly growth patterns.
• Margin and productivity initiatives: Although the Paragon acquisition is initially dilutive to margins, Mirion aims to offset this through operating leverage, procurement efficiencies, and broader adoption of in-house AI tools. Management believes that as acquisition synergies are realized and self-help measures expand, margin accretion will resume in the second half of the year.
• Rebound in medical segment: The medical segment is expected to return to growth, with mid-single-digit organic revenue increases anticipated in RTQA and sustained double-digit growth in nuclear medicine. New leadership and product launches are central to this recovery, but management cautions that lower hardware sales in dosimetry may limit upside.

Catalysts in Upcoming Quarters

Looking ahead, the StockStory team will be watching (1) whether Mirion can sustain strong order growth and convert its large nuclear power project pipeline into revenue, (2) the pace of integration and synergy realization from CertRec and Paragon, and (3) signs of margin recovery as procurement and AI initiatives scale. Progress in the medical segment’s rebound and the uptake of new AI-driven products will also be important indicators.

Mirion currently trades at $22.50, down from $23.44 just before the earnings. At this price, is it a buy or sell? Find out in our full research report (it’s free).

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