Viavi Exhibits More Than Threefold Growth in a Year: Should You Buy?

Viavi shares gained 268.5% over the past year as AI data-center demand, improved profitability and the Spirent acquisition supported growth. Fiscal 2026 revenue rose 40% year over year to $1.52 billion, non-GAAP EPS increased 112.8% to $1, and operating margin expanded 630 basis points to 20.6%; Q4 NSE revenue climbed 69.2% to $353.9 million. Management forecasts fiscal Q1 revenue of $450 million-$460 million and non-GAAP EPS of $0.40-$0.42, while the Zacks consensus estimate for fiscal 2027 EPS rose 165.6% over the past year to $1.62.

Analysis

The key question is whether recent earnings power is repeatable organically, not whether AI infrastructure is a growth theme. Test equipment can benefit as faster interfaces and denser systems raise validation complexity, potentially making testing spend less discretionary than some network hardware. But demand can still pause if hyperscalers defer deployments, and the article does not separate Spirent’s contribution from underlying growth or quantify data-center profitability.

Near term, the sharp rerating and rising estimates leave less room for an ordinary in-line quarter: the next catalyst is whether guidance converts into delivered revenue and sustained operating margin, not another AI narrative. Over 1–3 months, scrutinize organic NSE growth, acquired-business contribution, and integration costs. Over 6–18 months, 6G and AI-RAN are optionality, not a basis for underwriting near-term earnings until customer adoption and revenue are demonstrated.

Contrarian read: the business improvement may be real, while the article’s “buy now” conclusion skips valuation and attribution. A miss in organic growth could expose the stock to multiple compression even if reported results remain supported by the acquisition. Conversely, durable organic orders and margins would validate the premium. No valuation or consensus detail is supplied, so avoid a price-target claim.

Key Decisions for Investors

• Do not chase a fresh outright long solely on the bullish article. For existing positions, consider trimming into strength rather than assuming estimate upgrades will continue; the rally raises the bar for execution.
• Set an alert for the next earnings/guidance update: require evidence of organic NSE demand alongside Spirent contribution, and stable or improving operating margin, before adding. Verify segment-level acquisition contribution and integration costs, which are not provided here.
• Falsify the cautious view if organic NSE growth and margins remain resilient through the next report despite any integration burden; that would support retaining or adding exposure. A guidance reduction, weakening organic demand, or margin reversal would argue for reducing risk.
• Treat 6G, Wi-Fi and AI-RAN as longer-dated upside optionality rather than current earnings support until customer deployments or material revenue are disclosed.