Citi is positive on the multi-year growth of AI network infrastructure, with a focus on the impact of supply constraints on 2Q26 results
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Citi is positive on the multi-year growth of AI network infrastructure, with a focus on the impact of supply constraints on 2Q26 results
The report argues that upward revisions to Big Five cloud capex expectations benefit covered networking equipment companies, but tight supply of silicon, memory, and lasers could pressure second-half gross margins; LITE, KEYS, and CIEN are the top picks ahead of earnings, while CLS is the least preferred on a relative basis.
- Big Five U.S. cloud data center capex is expected to rise 83% YoY in 2026E, with a further 34% growth expected in 2027E.
- The Ethernet AI back-end switch market grew more than 100% YoY in 1Q26 to over $3.7 billion, and is expected to nearly double YoY in 2026 to almost $22 billion.
- The optical transport market grew 20% YoY in 1Q26 to over $4 billion, with CIEN ranking first with more than 25% share.
- Citi expects supply shortages in silicon switch chips, memory, and lasers to continue negatively affecting the networking equipment supply chain and gross margins in 2H26.
Report interpretation
Overview
This is Citi's preview report on 2Q26 earnings for the U.S. communications equipment industry, with the core theme centered on the tension between AI-driven network infrastructure growth and supply constraints. The report remains positive on the multi-year demand for networking equipment driven by AI, with particular focus on "stage 4" opportunities in the evolution of AI infrastructure, including early adoption of scale-up optics related to NPO and CPO.
Core views
Citi's core view is that cloud service provider capex expectations have been revised sharply upward, improving demand visibility for the networking equipment sector; however, tight supply of silicon, memory, and lasers in the supply chain could weigh on shipments, mix, and gross margins in 2H26. In relative rankings, LITE, KEYS, and CIEN are listed as the top buy-rated names ahead of earnings, while CLS, despite its leading share in the AI back-end switch market, is the least preferred on a relative basis due to customer concentration, supply pressure, and share pressure.
Analysis framework
The report combines Citi's five-stage AI infrastructure framework, the Big Five cloud data center capex model, Dell’Oro market data, and company customer exposure and margin sensitivity to rank communications equipment companies ahead of earnings. It focuses on comparing growth rates, share changes, and the impact of supply constraints across end markets such as front-end data center switching, AI back-end switching, campus switching, and optical transport.
Methodology notes
AI network infrastructure stage framework
Citi divides AI network infrastructure into multiple stages, and this report focuses on stage 4, namely early adoption opportunities in scale-up optics related to NPO and CPO.
Relative stock ranking based on supply constraints and margin impact
The report incorporates component shortages, product mix, indirect margin impact, and stage 4 exposure into relative rankings to determine preferences ahead of earnings.
Networking equipment end-market tracking
The report cites Dell’Oro data on quarterly growth, share, and annual outlook across front-end switching, back-end switching, campus switching, and optical transport markets.
Big Five cloud data center capex forecast
The report uses capex forecasts for AWS, Meta Compute, GSP, Azure, and OCI to assess the demand environment for cloud AI networking equipment.
Asset mapping & comparison
Structured mapping from thesis to named assets (strengths, weaknesses, peers, risks).
- LITEtop buy-rated pick
- Strengths
- Benefiting from demand in AI optics and scale-up optics, and included on Citi's top pick list ahead of earnings.
- Weaknesses
- The report does not provide detailed company-specific weaknesses.
- Comparison
- Preferred relative to CLS.
- Risks
- Tight laser supply and changes in the pace of AI optics demand.
- KEYStop buy-rated pick
- Strengths
- Benefiting from test and measurement demand tied to AI infrastructure build-out, and included on Citi's top pick list ahead of earnings.
- Weaknesses
- The report does not provide detailed company-specific weaknesses.
- Comparison
- Listed alongside LITE and CIEN as top buy-rated picks.
- Risks
- Changes in cloud capex pacing and volatility in the communications equipment supply chain.
- CIENtop buy-rated pick
- Strengths
- More than 25% share in the optical transport market, with 1Q26 revenue up nearly 40% YoY and strong demand from cloud service providers.
- Weaknesses
- Part of revenue depends on hyperscale cloud customers; in the April quarter, two hyperscalers contributed more than one-third of sales.
- Comparison
- Leads the optical transport market and outperforms most peers in share performance.
- Risks
- Fluctuations in cloud customer orders, optical transport market cyclicality, and supply chain constraints.
- CLSleast preferred pick
- Strengths
- Held more than 25% share in the AI back-end switch market in 1Q26, ranking first for the quarter, and has already shipped 1.6T in small volumes.
- Weaknesses
- Citi is least positive on it on a relative basis; market share declined by about 5 percentage points YoY, share losses among the top four cloud customers mainly shifted to CSCO, and customer concentration is high.
- Comparison
- Despite its strong market position, it is less attractive than LITE, KEYS, and CIEN.
- Risks
- Supply shortages, gross margin pressure, customer concentration, and share loss among cloud customers.
- ANETcovered company and market leader in front-end switching
- Strengths
- Leader in the front-end data center switch market, with nearly one-third share in the Top 4 cloud service provider segment, and 800G accounting for a double-digit percentage of its mix.
- Weaknesses
- Its back-end switch market share is in the low teens, and its campus switching share is about 3%.
- Comparison
- Leads CSCO by about 3 percentage points in front-end switching; trails CLS and NVDA in AI back-end switching.
- Risks
- Cloud customer capex timing, the 800G upgrade cycle, and supply chain constraints.
- CSCOcovered company and major networking vendor
- Strengths
- More than 50% share in the campus switching market, strong growth in cloud customer data center switching, and over 200bps share gain in optical transport.
- Weaknesses
- Still the fifth-largest vendor in the front-end cloud market, while enterprise customers still account for more than 70% of data center switching sales.
- Comparison
- Leads in campus switching, but trails ANET, CLS, and NVDA in front-end cloud and AI back-end switching.
- Risks
- Slowing enterprise demand, competition for cloud share, and supply chain and product mix pressure.
- NVDAAI back-end switch competitor
- Strengths
- Second-largest vendor in the AI back-end switch market with share in the mid-20% range, and plans to begin shipping Spectrum-X CPO in 2H.
- Weaknesses
- The report does not provide detailed company-specific weaknesses.
- Comparison
- Second only to CLS in the AI back-end switch market.
- Risks
- Uncertainty around CPO shipment timing and competition between Ethernet and InfiniBand ecosystems.
Key data
- Big Five U.S. cloud data center capex 2026E$730,926 millionThe table shows 83% YoY growth in 2026E, revised upward versus the April forecast, with estimates for META, MSFT, and AMZN raised.
- Big Five U.S. cloud data center capex 2027E$978,087 millionThe table shows 34% YoY growth in 2027E.
- Front-end data center switch market 1Q26mid-20s% Y/Y growthDell’Oro raised its 2026 outlook from mid-single-digit growth to mid-teens YoY growth.
- Ethernet AI back-end switch market 1Q26>$3.7B, >100% Y/Y growthThe market is expected to nearly double YoY in 2026 to almost $22 billion.
- Campus switch market 1Q26~$5B, mid-teens% Y/Y growthCSCO maintained more than 50% share, and ANET campus switching sales grew more than 20% YoY for the second consecutive quarter.
- Optical transport market 1Q26>$4B, 20% Y/Y growthCIEN ranked first with more than 25% share, while cloud customer revenue grew about 50% YoY.
- CLS customer concentrationGOOGL, META, AMZN = 58% of FY25 salesHigh cloud customer exposure brings demand upside but also amplifies customer and supply chain risk.
- ANET customer concentrationMSFT and META = 42% of FY25 salesCloud customer exposure supports its leadership in front-end switching.
Impact & implications
The report is broadly positive on the AI networking equipment chain, mainly supported by upward revisions to hyperscaler cloud capex and growing demand for AI switching and optical interconnects. From an investment perspective, companies with strengths in optical components, test and measurement, and optical transport, and with relatively manageable exposure to supply constraints, are more favored; however, caution is warranted for companies highly dependent on specific cloud customers and more exposed to component shortages in gross margins.
Risks
- Supply shortages in silicon switch chips, memory, and lasers could weigh on shipments and gross margins in 2H26.
- If cloud capex expectations are revised downward, support for networking equipment demand and valuations would weaken.
- Companies with high customer concentration face order volatility risk from a single or a few hyperscalers.
- New technologies such as 1.6T and CPO are still in early or pre-production stages, and mass production timing may fall short of expectations.
- Weakening optical transport demand in China could amplify seasonal pressure on vendors such as Huawei and ZTE.
What to watch
- CLS will be the first to report 2Q26 earnings on July 27.
- Watch whether capex guidance from cloud companies such as META, MSFT, and AMZN continues to be revised upward.
- Track the actual impact of silicon, memory, and laser shortages on 2H26 gross margins.
- Observe shipment timing and customer adoption of 1.6T, 800G, NPO, and CPO.
- Watch for further adjustments in Dell’Oro's 2026 outlook for front-end switching, back-end switching, and optical transport markets.