VIAVI (VIAV) Q4 2026 earnings review
AI Data Center Boom Drives Massive Acceleration
VIAVI delivered a blowout Q4, perfectly executing its strategic pivot away from legacy service providers and toward the Data Center and Aerospace & Defense (A&D) markets. Revenue surged 52.5% YoY to $443.1M, crushing historical growth rates. The operating leverage is staggering: Non-GAAP operating margin expanded by 960 bps to 24.0%, and Non-GAAP EPS skyrocketed 161.5% to $0.34. The Spirent acquisition is clearly paying off, and Q1 FY27 guidance strongly indicates this momentum is stable and continuing, with projected revenue growth sustaining above 52% YoY.
🐂 Bull Case
The Network and Service Enablement (NSE) segment grew 69.2% YoY. Hyperscalers and semiconductor vendors are heavily investing in 800G, 1.6T, and PCIe 6.0 test equipment to support massive AI infrastructure build-outs.
With a 40-45% flow-through on incremental revenue, VIAVI's profitability is scaling much faster than its top line. Guidance implies Non-GAAP EPS will jump another ~173% YoY in Q1 FY27.
🐻 Bear Case
While overall growth is spectacular, the traditional service provider and wireless test markets remain structurally weak, offering no near-term relief.
The rising stock price and conversion of debt have rapidly expanded the share count. Diluted shares jumped from 227.0M in 25Q4 to 261.0M in 26Q4, slightly muting per-share earnings power.
⚖️ Verdict: 🟢🟢
Highly Bullish. The company successfully re-engineered its revenue mix. The explosion in AI network testing is a durable secular tailwind, and management is translating top-line beats directly into massive margin expansion.
Key Themes
AI Data Center Test Demand is Accelerating
The core thesis for VIAVI is playing out flawlessly. The data center ecosystem—hyperscalers, NEMs, and semiconductor vendors—is driving exponential demand for high-speed Ethernet (800G/1.6T) and PCIe test equipment. This pushed the NSE segment to $353.9M, up 69.2% YoY. The shift from service providers to data centers as the primary customer base has fundamentally improved the company's growth profile.
Co-Packaged Optics & New Tech Insertions
Technology complexity is directly expanding VIAVI's Total Addressable Market (TAM). The shift toward Co-Packaged Optics (CPO) and silicon photonics requires entirely new test insertion points across the manufacturing process—from wafer-level to final assembly. Packaging is no longer an afterthought; it is a critical bottleneck, driving sustained demand for VIAVI's lab and production testing units.
Aerospace & Defense (PNT) Momentum
The A&D business, bolstered by the Innoal acquisition, remains a steady, high-margin driver. Strong demand for resilient Positioning, Navigation, and Timing (PNT) products for autonomous systems (like drones) continues to win Tier-1 US contractor deals, providing a stable growth floor beneath the volatile tech cycles.
Wireless Market Weakness is Stable but Persistent
The traditional wireless infrastructure test market remains a clear laggard. Management previously noted this segment was down 40-45% and did not expect a near-term recovery. While the data center explosion is masking this weakness at the consolidated level, wireless continues to act as a structural anchor on overall performance.
Share Count Dilution Accelerating
A key negative data point in an otherwise stellar print: GAAP diluted shares outstanding jumped to 261.0 million from 227.0 million a year ago (a 15% increase). This is largely driven by the rising stock price triggering conversion premiums on their senior convertible notes. If the stock continues to rise, further dilution will act as a headwind to EPS growth.
Macro & Supply Chain Pressures (Memory Deficits)
While VIAVI is managing it well by aggressively building inventory and paying premium prices for early access to components, the broader macro environment poses risks. The industry faces projected memory supply deficits through the end of the decade, and any miscalculation in forecasting could lead to lead-time disruptions. Furthermore, geopolitical tariffs remain an ongoing background cost.
Other KPIs
Accelerating. The margin expansion story is extraordinary. Non-GAAP operating margin surged from 14.4% in 25Q4 to 24.0% this quarter. The company previously cited a 40-45% flow-through on incremental NSE revenue, and this quarter’s $152.6M YoY revenue increase clearly fell straight to the bottom line.
Stable. OSP revenue grew 9.6% YoY. While vastly overshadowed by the NSE segment, it provides consistent, high-margin cash flow (historically pushing near 40% operating margins). The anti-counterfeiting recovery continues to hold up the segment despite mature dynamics in 3D sensing.
Strong cash generation in the quarter allowed the company to continue its aggressive debt management strategy. For the full year, operating cash flow reached $113.9 million. VIAVI ended the quarter with $656.7 million in total cash and short-term investments, providing ample liquidity.
Guidance
Accelerating/Stable at high levels. The midpoint of $455M implies a 52.1% YoY growth rate against 26Q1's $299.1M. This firmly dispels any concerns that Q4 was a one-time peak, proving the data center momentum is a multi-quarter secular trend.
Accelerating heavily. The midpoint of $0.41 represents a massive 173% YoY increase compared to $0.15 in Q1 FY26. It also represents strong sequential growth from Q4's $0.34, pointing to continued gross margin benefits and tight expense control.
Key Questions
Margin Ceiling
With Non-GAAP operating margins reaching 24.0% this quarter, how much further can the 40-45% incremental revenue flow-through push this metric? Is a 30% operating margin attainable in the next 12-18 months?
Spirent Revenue Trajectory
How much of the $450-$460M Q1 FY27 revenue guidance is organic versus inorganic contribution from the Spirent acquisition, and how has Spirent's annualized run-rate evolved since the initial $200M projection?
Wireless Recovery Timeline
Given the persistent weakness in traditional wireless infrastructure test, are there any leading indicators—such as early AI-RAN or 6G R&D—suggesting a bottom is forming for calendar year 2027?