Keysight's CSG Gains Momentum: Can AI Infrastructure Drive Growth?

Keysight's Communications Solutions Group generated $1.35 billion in fiscal Q3 2026 revenue, up 43% year over year, with a 70.8% gross margin and 34.0% operating margin. Commercial Communications revenue rose 56% to a first-ever $1.006 billion, while Wireline revenue more than doubled on AI data-center and high-speed connectivity testing demand. Keysight guided fiscal Q4 revenue to $1.93-$1.95 billion, implying approximately 37% year-over-year growth at the midpoint, while 2026 and 2027 earnings estimates have improved over the past 60 days.

Analysis

KEYS is transitioning from a cyclical wireless-test supplier toward a higher-value AI interconnect bottleneck: every increase in Ethernet speed, optical complexity, and rack-scale architecture raises required validation intensity before deployment. This should support mix-led margin resilience, but the market has likely already capitalized much of the near-term growth after the stock's sharp rerating; the next 1-3 month catalyst is whether backlog, book-to-bill, and fourth-quarter guide demonstrate that demand is broad-based rather than concentrated in a small set of hyperscale programs.

VIAV is the more direct read-through but has a different risk profile: its network-service and field-test exposure can lag laboratory and production test demand, making it a potentially higher-beta second derivative if cloud buildouts translate from equipment qualification into deployment. TER benefits from AI semiconductor test, yet its earnings sensitivity remains meaningfully exposed to memory and industrial recovery; a broad AI-test basket conflates these distinct cycles. The competitive issue for KEYS is not principally share loss, but customer insourcing and capex digestion once leading AI clusters standardize designs.

Contrarian view: 6G spending is not an investable earnings driver over the next 12-18 months; funded R&D programs are small relative to eventual deployment capex and can be delayed. The more material downside is that AI infrastructure customers shift toward fewer, standardized optical/electrical configurations, reducing incremental test content per dollar of capex. Thesis fails constructively if KEYS sustains order growth above revenue growth for two quarters and expands operating margin despite mix normalization; negatively, a sub-1.0x CSG book-to-bill or a guide reduction tied to hyperscaler timing would signal digestion.

Key Decisions for Investors

• Maintain a tactical long KEYS for the next earnings cycle only if shares consolidate near or below the sector multiple; target 10-15% upside on upward FY2027 EPS revisions, with a 7-8% stop or exit on CSG book-to-bill below 1.0x.
• Express relative AI-connectivity exposure via long KEYS / short TER in equal dollar beta-adjusted size over 3-6 months. KEYS has cleaner exposure to data-center interconnect test, while TER retains greater memory, industrial, and robotics-cycle sensitivity; close if memory pricing/revisions accelerate materially or TER's AI test mix expands faster than expected.
• Place VIAV on a deployment-phase watchlist rather than chase. Initiate only after evidence of sustained orders and margin conversion; the trigger is sequential NSE growth with stable gross margin, which would validate field and service-test follow-through from lab qualification demand.
• Avoid assigning valuation credit to 6G before 2028. Monitor carrier capex budgets and 3GPP milestones as long-duration optionality, not near-term underwriting inputs.