MRCY Mercury Systems

Research status: Primary-source verified through the FY2026 10-K and late-August 2026 insider filings; refreshed 1 September 2026 for the weekly holding review. Current market reference: $87.33 close on 31 August 2026.

Mercury's operating recovery is real but still incomplete. Q4 FY2026 bookings were a record $660M, +93% YoY, with 2.28x book-to-bill; total backlog exceeded $1.9B, including $996M expected to convert within 12 months. Q4 revenue was $290M, adjusted EBITDA $49M at a 16.7% margin, operating cash flow $42M, and free cash flow $29M. Full-year revenue was $984M, adjusted EBITDA $150M, and FCF $68M. Net debt ended Q4 at about $227M, down 19.5% YoY.

The FY2026 10-K adds important risk calibration rather than a thesis break. RTX represented 15% of FY2026 revenue, Lockheed Martin 11%, and Northrop Grumman 10%; five customers represented 54% of accounts receivable, unbilled receivables and costs in excess of billings at year-end. Mercury also had $269.2M of non-cancelable purchase commitments, increasing the importance of clean backlog conversion and inventory discipline. Offsetting these risks, KPMG and management concluded internal control over financial reporting was effective as of July 3, 2026; Mercury was in compliance with revolver covenants; and pending legal matters were not expected to have a material impact.

Late-August CEO Form 4 sales do not independently weaken the thesis: the disclosed sales were tied to option exercises and intended to cover exercise price, withholding taxes and transaction costs. No newer company press release or SEC filing was identified after the August 27 filings as of this refresh.

The evidence therefore supports maintaining the existing starter, but not adding at current prices. Holding the existing PowerFund scenario values constant, the approximately $98.5 probability-weighted 24-month value implies only about 6.2% annualized return from $87.33, while the existing $62 bear case implies roughly 29% downside. Keep the existing MRCY starter and defer the planned add. Reconsider additional capital if the stock falls to roughly $75 or below without thesis deterioration, or if evidence materially raises the 24-month earnings/FCF trajectory.

Investment case

Mercury supplies secure, rugged, open-architecture processing, RF/sensor and mission-computing technology for aerospace and defence platforms. Its systems are designed into long-lived defence programmes, creating qualification, integration, security and lifecycle switching costs.

The PowerFund thesis is:

> MRCY is a defence-electronics turnaround with record multi-year demand: approximately $1.95B of backlog and a 1.57x FY2026 book-to-bill should drive low-double-digit organic growth, while replacement of legacy low-margin backlog, higher production scale and factory automation can lift adjusted EBITDA margins from 15.3% in FY2026 toward 20%+ by FY2028, causing earnings and cash flow to grow substantially faster than revenue.

The Q4 presentation materially improves confidence in four parts of the thesis:

1. Demand is broad-based. Q4 included significant production awards across Common Processing Architecture (CPA), effectors, airborne applications, space and missile defence.

1. CPA is showing strategic momentum. Mercury reported its largest-ever quarter for CPA bookings and believes the result reflects differentiation of its CPA solutions.

1. The defence spending cycle is becoming multi-year. Management is beginning to see multi-year customer commitments as stronger defence budgets convert into firm production demand.

1. The margin bridge is explicit. Management expects backlog-margin expansion as legacy low-margin backlog converts, operational simplification/automation, and positive operating leverage from higher organic growth.

The remaining investment debate is no longer whether Mercury has demand. It is whether the company can convert that demand without repeating its historical programme, supply-chain and manufacturing execution problems.

Verified operating baseline

Q4 FY2026

• Bookings: $659.6M, up 93% YoY.
• Book-to-bill: 2.28x, versus 1.25x in Q4 FY2025.
• Backlog: $1.945B, up 38%.
• 12-month backlog: $996.0M, up approximately 23%.
• Revenue: $289.8M, up 6%.
• Gross margin: 30.6%, down 40 bps YoY.
• Adjusted EBITDA: $48.5M, down 5%.
• Adjusted EBITDA margin: 16.7%, versus 18.8%.
• Adjusted EPS: $0.37, down 21%.
• Operating cash flow: $42.2M, up 11%.
• Free cash flow: $28.6M, down 16%.
• FCF / adjusted EBITDA: 58.9%.

Q4 margin softness means the operating-leverage thesis is not yet fully proven even though forward guidance is considerably stronger than the trailing-quarter comparison.

FY2026

• Bookings: $1.546B, up 49.8%.
• Full-year book-to-bill: 1.57x, versus 1.13x.
• Revenue: $983.6M, up 7.9%.
• Gross margin: 28.6%, up 70 bps.
• Adjusted EBITDA: $150.2M, up approximately 25.7%.
• Adjusted EBITDA margin: 15.3%, up 217 bps.
• Adjusted EPS: $1.06, up 66%.
• Operating cash flow: $102.4M.
• Free cash flow: $68.1M.
• FCF / adjusted EBITDA: 45.3%.

Additional indicators:

• Domestic revenue represented approximately 85.8% of FY2026 revenue and grew 13.0% organically YoY.
• Q4 over-time revenue grew 23.6% YoY to its highest level in 15 quarters, driven largely by improved material availability.
• Net working capital ended around $431M, down approximately $18M / 4% YoY while revenue grew.
• Cash ended at $214.3M.
• Debt ended at $441.5M, down $150M sequentially.
• Net debt ended around $227M, down approximately $55M / 19.5% YoY.
• Inventory ended at $367.0M, versus $332.9M a year earlier.
• FY2026 capex was $34.3M, versus $19.8M.

FY2027 management outlook

• Revenue approaching $1.1B.
• Revenue growth approaching double digits.
• Q1 revenue expected to be the lowest of the year but still up high single digits YoY, with revenue increasing through the balance of FY2027.
• Adjusted EBITDA approaching $200M, nearly +30% YoY.
• Adjusted EBITDA margin in the high teens and generally increasing through the year.
• FY2027 FCF conversion expected around 35%, below the 50% long-term target because of investment in inventory, automation and factory optimisation.
• Q1 expected to be a larger-than-normal cash outflow because Mercury will receive materials needed for the production ramp.

At approximately $200M adjusted EBITDA and 35% FCF conversion, FY2027 FCF would be roughly $70M.

FY2028 reference point

Management's initial FY2028 reference framework is:

• Low-double-digit organic revenue growth.
• Adjusted EBITDA margin around the low end of the 20–25% target profile.
• FCF conversion returning toward the 50% target.

If FY2027 revenue reaches approximately $1.1B and FY2028 organic growth is around 10–12%, FY2028 revenue could reach approximately $1.21–1.23B. At approximately 20–21% adjusted EBITDA margin, this implies around $240–260M adjusted EBITDA, before assuming upside from additional defence-production tailwinds or Palantir-enabled automation.

KPI ladder

This ladder is now the primary evidence test for the investment thesis.

Valuation scenarios

Using the $105.00 regular-session close on 18 August 2026:

• Market capitalisation: approximately $6.24B.
• Net debt: approximately $227M.
• Enterprise value: approximately $6.47B.
• EV / FY2026 adjusted EBITDA: approximately 43x.
• EV / FY2027 management EBITDA outlook of ~$200M: approximately 32x.
• Trailing FCF yield: approximately 1.1%.

This remains a premium valuation.

24 months

PowerFund scenarios below are anchored to management's FY2027/FY2028 framework but are PowerFund assumptions, not company guidance.

Probability-weighted working value at the $105 valuation basis remains around $100.

The stronger Q4 print raises confidence in the operating pathway but does not make the $105 reference price obviously cheap. The risk/reward improves materially if post-print weakness produces a lower entry price without deterioration in the FY2027/FY2028 operating framework.

60 months

The five-year thesis is more attractive than the two-year valuation setup because upside comes from revenue compounding plus margin expansion, not simply a higher valuation multiple.

• Conversion of approximately $996M of 12-month backlog into revenue without material programme charges, schedule slippage or working-capital deterioration.

• FY2027 revenue approaching $1.1B and adjusted EBITDA approaching $200M.

• FY2027 adjusted EBITDA margin reaching the high teens and generally increasing through the year.

• FY2028 adjusted EBITDA margin moving toward 20%+, consistent with the low end of the company's long-term 20–25% target range.

• FY2028 FCF conversion returning toward the 50% target after the planned FY2027 inventory/factory-investment cycle.

• Book-to-bill remaining above 1.0 after FY2026's exceptional 1.57x.

• Continued strong CPA awards after Mercury's largest-ever CPA bookings quarter.

• Additional multi-year commitments across effectors, airborne applications, space, munitions and missile defence.

• Additional defence-budget tailwinds that are not included in management's current FY2027/FY2028 reference framework.

• Palantir-enabled planning and factory automation producing measurable improvements in backlog conversion, inventory turns, lead times, throughput and margins; management currently assumes no benefit from this initiative in its FY2027/FY2028 reference outlook.

• Further debt reduction as production and cash conversion improve.

• Execution remains the central risk. Mercury has historically struggled to convert programme demand into clean revenue, margins and free cash flow.

• Customer concentration is material. RTX represented 15% of FY2026 revenue, Lockheed Martin 11%, and Northrop Grumman 10%. A loss, insourcing decision, programme delay or pricing reset at a major prime could materially affect results.

• Receivables/programme concentration is also high. Five customers represented 54% of accounts receivable, unbilled receivables and costs in excess of billings at July 3, 2026, increasing dependence on a relatively small set of programme conversions and collections.

• Purchase-commitment and working-capital risk. Mercury had $269.2M of non-cancelable purchase commitments at year-end while inventory was $367M and management plans additional FY2027 inventory/factory investment. Failure to convert funded demand into shipments would pressure cash flow.

• Q4 margin evidence was mixed. Revenue rose 6%, but adjusted EBITDA declined 5% and adjusted EBITDA margin fell to 16.7% from 18.8%.

• FY2027 FCF will remain suppressed by design. Management expects only approximately 35% conversion because inventory and factory investment are required for the production ramp; full cash-flow proof is therefore delayed until FY2028.

• Fixed-price/programme execution: cost overruns, schedule delays, quality problems, EAC losses and supply-chain failures can erode the expected backlog-margin improvement.

• Booking lumpiness: the 2.28x Q4 book-to-bill should not be extrapolated mechanically even though the 1.57x full-year figure is also very strong.

• Prime-contractor bargaining power: customers can dual-source, insource systems, change architecture or pressure programme economics.

• Valuation remains premium. The current two-year probability-weighted return is below the PowerFund hurdle despite the post-earnings correction.

• Adjusted-earnings quality and dilution: stock-based compensation remains material and diluted share count has risen.

• Defence-budget/procurement timing: long-term spending is supportive, but continuing resolutions, shutdowns, procurement changes or programme delays can shift award timing.

• Legal/covenant risk is presently contained rather than absent. The FY2026 10-K says pending legal matters are not expected to be material, internal controls were effective, and Mercury was in compliance with its revolver covenants at year-end.

Warning — investigate and freeze additions

• FY2027 organic revenue growth runs materially below high single digits despite approximately $996M of 12-month backlog.

• Adjusted EBITDA margin fails to progress into the high teens during FY2027.

• Two-quarter trailing book-to-bill falls below 1.0, or backlog begins declining materially despite healthy defence demand.

• Inventory rises sharply without corresponding backlog conversion and revenue acceleration.

• New programme/EAC charges indicate that the record backlog has structurally poor economics.

• FCF weakness materially exceeds management's planned FY2027 investment cycle without a clear working-capital explanation.

• Valuation exceeds approximately 30x credible two-year adjusted EBITDA while FY2027/FY2028 earnings expectations stop improving.

Reduce — normally trim 25–50%

• FY2027 revenue growth falls below approximately 5–7%.

• Adjusted EBITDA margin remains below approximately 16% through the second half of FY2027.

• Backlog declines more than approximately 10% from the $1.945B peak without a temporary timing explanation.

• Book-to-bill remains below 1.0 for two consecutive quarters.

• A major programme delay, cancellation or adverse EAC change reduces expected normalised EBITDA power by approximately 10–20%.

• Net debt begins rising materially because production growth consumes structurally excessive working capital.

• Adjusted earnings increasingly diverge from GAAP/per-share economics because of persistent stock compensation, restructuring, litigation or programme adjustments.

Invalidate — exit unless explicitly re-underwritten

> Invalidate if the record backlog fails to translate into approximately 10% organic growth and high-teens adjusted EBITDA margins during FY2027, or if Mercury cannot demonstrate a credible path toward approximately 20%+ adjusted EBITDA margins and ~50% FCF conversion in FY2028 — evidence that programme-execution problems or poor backlog economics are structural rather than temporary.

Additional hard invalidators:

• A structural customer or programme loss reduces normalised EBITDA power by more than 20%.

• Recurring programme losses and execution problems return despite healthy aerospace and defence demand.

• Debt/covenant/liquidity pressure constrains investment or forces dilutive capital raising.

• Evidence shows Mercury's modular/open processing architecture is being structurally displaced or materially insourced by primes or government customers.

Mercury competes with specialist embedded-compute and defence-electronics suppliers, vertically integrated capabilities inside major defence primes, and customer insourcing.

Its differentiation is based on:

• qualification into long-lived aerospace and defence programmes;
• secure/trusted domestic manufacturing;
• ruggedisation and mission-critical reliability;
• open/modular architectures that allow advanced commercial compute technology to be deployed in defence environments;
• integration expertise across processing, RF, sensors and mission systems; and
• meaningful switching/requalification costs once systems are designed into a programme.

The FY2026 record bookings and $1.945B backlog are strong evidence that Mercury is currently winning production demand. The company's largest-ever CPA bookings quarter is particularly encouraging for its position in secure common processing.

The moat is nevertheless not a monopoly. Large primes retain substantial bargaining power, alternative suppliers exist, and architecture can be insourced. The correct evidence bar remains backlog conversion, improving backlog margin, high-teens/20%+ adjusted EBITDA margins and free-cash-flow conversion.

1. Track conversion of the $996M next-12-month backlog into revenue, especially programs moving from development to production.
2. Track the gap between total backlog (~$1.9B) and the $1.082B of remaining performance obligations disclosed in the 10-K, including cancellation/funding characteristics and timing.
3. Verify sustained adjusted EBITDA margin progression rather than relying on one strong Q4.
4. Track free-cash-flow conversion versus EBITDA and working-capital normalization; require evidence that FY26's $68M FCF is the beginning of a durable recovery.
5. Monitor inventory, the $269.2M non-cancelable purchase-commitment base, and whether material receipts convert into shipments rather than structurally higher working capital.
6. Monitor exposure to RTX, Lockheed Martin and Northrop Grumman for programme delays, insourcing or bargaining-pressure evidence.
7. Track net debt reduction, interest burden and revolver covenant headroom.
8. Assess whether the Palantir factory-automation program measurably reduces material-planning friction, lead times and working capital.
9. Rebuild the 24-month scenario after the next quarterly print. Consider adding only if either (a) price is roughly $75 or lower with the thesis intact, or (b) revised fundamentals lift the probability-weighted 24-month return to a clearly attractive level.