Fortinet (FTNT Quick QuoteFTNT - Free Report) shares have rallied 119.9% in the past six-month period, outperforming the Zacks Security industry and the broader Computer and Technology sector’s growth of 135% and 32.1%, respectively. This outperformance reflects confidence in Fortinet's execution, a run that may tempt investors to book profits.

However, the rally appears to be rooted in strengthening fundamentals rather than speculative enthusiasm. Accelerating product demand tied to AI workloads, a raised 2026 outlook, an improving services trajectory, and a steady cadence of AI security innovation suggest the cybersecurity leader still has room to run in the near term. Here are three reasons to buy FTNT stock now.

FTNT’s 6-Month Price Performance

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SASE Firewall and AI Infrastructure Demand Fuel Product Momentum

Fortinet's strategy of integrating networking and security on a single operating system, FortiOS, powered by its proprietary FortiASIC chips, resonates strongly with enterprises modernizing infrastructure for AI. In the second quarter of 2026, revenues climbed 26% year over year to $2.05 billion, as product revenues soared 52% to $773 million on robust FortiGate unit growth and higher average selling prices. Billings jumped 33% to $2.37 billion. The newly framed SASE Firewall business, which combines Secure Networking and Unified SASE, grew 34% to more than $2 billion. FortiSASE billings more than doubled, while operational technology billings rose over 55%. Fortinet also secured an eight-figure deal from a neocloud provider to protect AI data centers, underscoring its price-to-performance advantage. Customer investments to secure AI workloads and mitigate AI-related risks drove both new business and upgrade activity across the installed base.

Raised 2026 Guidance Signals Durable Growth

Management raised its 2026 outlook across all top-line metrics. Fortinet now expects revenues of $8.02-$8.18 billion, implying 19% growth at the midpoint, up from the prior guidance of $7.71-$7.87 billion. Billings are projected between $9.35 billion and $9.55 billion, indicating 25% growth, while service revenues are expected to be in the range of $5.18-$5.22 billion. Non-GAAP operating margin guidance was lifted to 35-37%, and non-GAAP earnings are expected to be in the range of $3.41-$3.47 per share. Non-GAAP gross margin is expected to be in the 79-81% band for 2026. Importantly, management believes the first quarter of 2026 marked the trough for service revenue growth, with service billings already accelerating 26% in the second quarter.

For the third quarter, Fortinet projects revenues of $2.01-$2.10 billion and billings of $2.25-$2.35 billion. Infrastructure investments are expected to be in the range of $350-$550 million for 2026 and $100-$150 million for the third quarter. On Oct. 2, Fortinet announced that it will report third-quarter 2026 results on Oct. 28, a near-term catalyst that could validate this momentum.

The Zacks Consensus Estimate for Fortinet's earnings is pegged at $3.42 per share for 2026, which implies year-over-year growth of 23.91%.

Expanding AI Security Portfolio and Financial Flexibility

Fortinet keeps sharpening its AI security edge. On Aug. 17, 2026, the company acquired Virtue AI, adding agentic AI red-teaming, continuous AI validation, agent governance and real-time guardrails that complement its FortiAIGate solution for protecting large language models. On Sept. 10, Fortinet was named a Leader in the 2026 Gartner Magic Quadrant for Hybrid Mesh Firewall, positioned highest for Ability to Execute for the second straight year. On Sept. 15, it opened a company-owned Innovation Hub in New York City, an investment of more than $60 million that includes a Fortinet Cloud point-of-presence data center. Financially, free cash flow more than tripled year over year to $966 million in the second quarter, while Moody's upgraded its debt rating to A3.

FTNT's Valuation & Competitive Landscape

From a valuation standpoint, FTNT appears overvalued, trading at a forward 12-month price-to-earnings ratio of 48.59, higher than the sector's average of 21.33. The company carries a Value Score of F, though the premium is justified by Fortinet's superior margin profile, raised guidance trajectory and expanding AI- and SASE-driven total addressable market.

FTNT’s Valuation

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Competition in AI-driven security remains intense and fragmented. Palo Alto Networks (PANW Quick QuotePANW - Free Report) continues to push platformization across network security, SASE and security operations, and Palo Alto Networks' Cortex suite targets the same AI SOC opportunity as FortiSOC. CrowdStrike (CRWD Quick QuoteCRWD - Free Report) leverages its cloud-native Falcon platform to expand from endpoint protection into next-gen SIEM, while CrowdStrike's agentic AI capabilities intensify competition for SecOps budgets. Cisco (CSCO Quick QuoteCSCO - Free Report) bundles security with its massive networking installed base, and Cisco's Hypershield and Splunk assets strengthen its AI security pitch. However, Fortinet's in-house FortiASIC technology, single FortiOS platform and on-premises Sovereign SASE offering provide a cost and performance edge that Palo Alto Networks, CrowdStrike and Cisco may find quite difficult to replicate.

Conclusion

Fortinet's 119.9% six-month rally is backed by solid fundamentals, including accelerating AI-driven product demand, raised 2026 guidance, an inflecting services business and an expanding AI security portfolio. Robust free cash flow and an investment-grade balance sheet add financial flexibility. Investors should consider buying FTNT stock now to capitalize on its near-term growth momentum.

Fortinet currently sports a Zacks Rank #2 (Buy). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.