Mercury Systems (MRCY) Q4 2026 earnings review
A Historic Backlog Boom Masks Near-Term Profitability Pains
Mercury Systems delivered a spectacular demand quarter, securing a record $660 million in Q4 bookings—nearly double its previous best. This 2.28 book-to-bill ratio provides massive forward visibility and pushes total backlog to $1.9 billion. However, the surge in volume completely bypassed the bottom line. GAAP Net Income evaporated, plunging 95% year-over-year to just $0.8 million, weighed down by a massive $10M spike in stock-based compensation and difficult prior-year comps. While management projects strong FY27 revenue growth approaching $1.1 billion, they are actively warning that free cash flow conversion will drop to 35% as the company aggressively invests in inventory to feed this historic backlog.
🐂 Bull Case
A staggering 93% YoY bookings increase in Q4 fundamentally derisks the top-line narrative for the next 18-24 months. The transition from legacy backlog to fresh, high-demand production orders is fully underway.
Years of pipeline conversations regarding elevated global defense budgets are finally crossing the finish line into firm, multi-year production orders for Common Processing Architecture (CPA) and effectors.
🐻 Bear Case
Despite 6% revenue growth in Q4, GAAP net income fell to near-zero ($0.8M), and Adjusted EBITDA declined 5%. The disparity between top-line euphoria and bottom-line reality is glaring.
Scaling this growth is capital-intensive. Management is guiding FY27 free cash flow conversion down to 35%, significantly below their 50% long-term target, with Q1 specifically facing a large outflow to fund working capital.
⚖️ Verdict: ⚪
Neutral. The sheer magnitude of the bookings win guarantees revenue growth, but the deteriorating cash conversion and poor GAAP profitability prove that scaling this business remains a highly capital-intensive and margin-dilutive process in the near term.
Key Themes
Historic Bookings Surge
Accelerating. Bookings skyrocketed 93% YoY to $660M in Q4, delivering a massive 2.28 book-to-bill ratio. This single quarter pushed total backlog to a record $1.94 billion. It highlights broad-based strength across Common Processing Architecture (CPA), airborne applications, and space.
Macro Defense Tailwinds Finally Landing
Accelerating. For the past year, management described global rearmament and domestic initiatives as potential upside 'not yet in the plan.' Q4 proves these macro defense budgets are finally crossing the finish line into firm, multi-year production commitments.
GAAP Profitability Collapses Despite Sales Growth
Reversing. In stark contrast to the positive revenue narrative, GAAP net income plunged 95% YoY to just $0.8M. The primary culprit was a massive surge in operating expenses—specifically stock-based compensation, which jumped from $4.2M in 25Q4 to $14.8M this quarter. This severely dilutes the quality of the top-line beat and is a major red flag if this becomes the new structural run-rate.
Palantir AI Factory Integration
Stable. Mercury announced a strategic agreement with Palantir to leverage AI software for material planning and factory operations. Given the company's historical struggles with supply chain bottlenecks and lumpy backlog conversion, this is a highly targeted tech innovation aimed directly at their core operational bottleneck.
Free Cash Flow Sacrificed for Growth
Decelerating. Generating cash remains a structural challenge during ramps. Management is guiding FY27 free cash flow conversion down to ~35%, explicitly abandoning their 50% long-term target in the near term. The company is forcing a 'larger outflow than normal' in 27Q1 just to build enough inventory to execute on its backlog.
Margin Compression YoY
Stable. Despite the massive volume, Q4 Adjusted EBITDA margin compressed to 16.7% from 18.8% a year ago. While FY26 total margins expanded, the Q4 YoY step-back highlights that scaling up new production programs still carries heavy upfront costs compared to the mature delivery pull-forwards seen in late FY25.
Other KPIs
Stable. Up 70 basis points year-over-year. This steady improvement validates management's ongoing narrative that they are slowly but successfully burning through legacy low-margin contracts and replacing them with better-priced production runs.
Accelerating. Down 19.5% year-over-year from $282 million in Q4 FY25. Despite the lumpiness in quarterly cash flows, the company has maintained discipline in deleveraging the balance sheet over a multi-year horizon.
Guidance
Accelerating. Management guided for 'approaching double digits' YoY growth. This reverses the single-digit grind of FY26 (+7.9%) and signals that the massive Q4 bookings are expected to convert to revenue quickly.
Accelerating. Represents nearly 30% YoY growth from FY26's $150 million. The high-teens margin outlook implies that operating leverage is finally expected to outpace operating expense growth, provided stock-based compensation normalizes.
Decelerating. A step down from the 45.3% achieved in FY26, as working capital demands bite. Management explicitly flagged targeted investments in inventory and factory automation to support the revenue ramp.
Key Questions
Stock-Based Comp Run-Rate
Q4 saw stock-based compensation jump over 250% YoY to $14.8M. How much of this was a one-time true-up versus the new structural run-rate for FY27?
Palantir ROI
What specific margin or backlog-conversion velocity improvements are embedded in the FY27 guidance resulting from the new Palantir AI integration?
Q1 Cash Outflow Severity
You warned of a 'larger outflow than normal' in Q1 FY27. Can you quantify the expected working capital build required to support the new $660M in bookings?