Fortinet Q3 2026: revenue up 20% to $2.08B, but hardware margin fell and service outlook was trimmed

Fortinet sells network security. Most of it is firewalls: the FortiGate hardware boxes and software that sit between a company's network and the internet. It also sells the subscriptions that keep those firewalls updated against new threats, plus technical support. In the third quarter of 2026 (July–September), revenue rose 20% to $2.08 billion. Hardware led again: product revenue grew 37% to $765.0 million, while service revenue (the recurring subscription and support business) grew 13% to $1.31 billion. Diluted earnings per share (EPS, profit divided by all shares including those that could be created from stock awards) rose 39% to $0.86.

This analysis is written from the October 28 earnings release (8-K Exhibit 99.1). The full Q3 10-Q has not been filed yet, so the release's tables are all there is for now. They give no breakdown by region or service line, and no management explanation of why individual lines moved.

Key figures

*Non-GAAP figures are the company's own adjusted measures from the release. They exclude stock-based compensation ($82.0M this quarter), amortization of acquired intangibles, a small intellectual-property gain and the $17.0M escrow gain, and they apply a flat 18% tax rate.

First nine months (January–September 2026): revenue $5,975.9M (+22.1%), product revenue $2,183.1M (+42.9%), service revenue $3,792.8M (+12.6%), operating income $1,973.6M (+35.3%), net income $1,776.3M (+31.8%), diluted EPS $2.39 vs. $1.75.

Takeaway: Fortinet's growth is becoming more dependent on hardware, and hardware is becoming less profitable. Product revenue grew 37% while product gross margin fell to 64.4%, from 67.7% a year ago and 69.8% in Q2. Management also trimmed its full-year service revenue range by $40 million at the midpoint while raising total revenue by $70 million. The extra revenue it expects now comes entirely from boxes, the lower-margin part of the business. The firewall upgrade wave is real. What isn't showing up yet is the payoff the bull case depends on: faster subscription growth from all that newly installed hardware.

Hardware: still growing fast, but at a lower margin

Product revenue of $765.0 million was up 37% year over year but slightly down from Q2's $773.0 million. Year-over-year growth slowed from 52% in Q2, partly because the price increases Fortinet made earlier are starting to show up in the year-ago comparison.

The bigger change is profitability. Product cost of revenue rose 51% ($272.6M vs. $180.7M), well ahead of the 37% sales growth, so product gross profit grew only 30%. Product gross margin was 64.4%, against 67.7% a year earlier and 69.8% in Q2. Because the 10-Q isn't out yet, the company hasn't explained the drop. In the Q2 10-Q, though, management said product gross margin "may decline" for the full year on higher hardware component costs, and cited "increased costs of memory chips." Q3 looks like that warning arriving. The Q4 guide points the same way: non-GAAP gross margin for the whole company of 78–80%, below Q3's 79.6% at the midpoint.

Inventory supports that read. It stood at $591.2 million at September 30, up 48% from $399.5 million at December 31. Accounts payable (bills owed to suppliers) rose 86% to $430.3 million. Fortinet is building stock and buying more from contract manufacturers. That fits strong demand, rising component costs, or both. The release doesn't say which.

Services and billings

Service revenue rose 12.7% to $1.31 billion, a little slower than Q2's 13.7%. The release doesn't split it between security subscriptions (FortiGuard) and technical support (FortiCare). It also gives no separate figure for unified SASE (Fortinet's cloud-delivered security for remote users and branches) or SecOps (its security-operations tools). Its business highlights do announce two new subscription products: a FortiGuard AI security service and a FortiLink SASE service for small branches. Neither contributed measurable revenue yet.

Service gross margin improved to 87.4% from 87.0%, so the margin squeeze is confined to hardware.

Billings (revenue plus the change in deferred revenue, roughly what was invoiced in the quarter) grew 29% to $2.34 billion. That came in near the top of the company's $2.25–2.35 billion guide, though it was slightly below Q2's $2.37 billion. Deferred revenue is cash billed for services that will be counted as revenue later. It rose $258.7 million in the quarter to $7.93 billion. Using the year-ago quarter's $82.8 million increase, that works out to roughly 19% year-over-year growth. The long-term portion ($3.97B) now slightly exceeds the short-term portion ($3.96B). Customers are signing longer contracts, which lifts billings now but spreads the revenue over more years.

What the headline numbers hide

• GAAP EPS grew much faster than the business. Pre-tax income rose 26.9% ($755.0M vs. $594.8M). Net income rose 34.1% because the effective tax rate fell to 15.8% from 20.3%. Had the tax rate stayed at last year's level, net income would have grown about 27%. The release doesn't explain the lower rate. The company's own non-GAAP figures (flat 18% tax) show EPS up 23%, not 39%.
• A one-off gain. GAAP net income includes a $17.0 million gain from settling an escrow tied to a past acquisition. It is booked below operating income and excluded from non-GAAP results. Strip it out as well and pre-tax income grew about 24%.
• Buybacks helped, but none happened this quarter. Diluted shares were 2.4% lower than a year ago (742.6M vs. 761.2M). That came from buying back shares in 2025 and early 2026, and it added roughly 2.5 points to EPS growth. Fortinet repurchased no stock in Q3: nine-month repurchases of $972.8 million equal the first-half figure. Diluted shares actually rose from 739.9 million in Q2. The board added $1.2 billion to the buyback authorization, leaving $2 billion available. The company also pays no dividend.
• Operating profit is the clean part. Operating income rose 28.7% on 20.5% revenue growth because operating expenses grew only 10.7%. Sales and marketing fell to 32.0% of revenue from 33.8%, and R&D to 10.3% from 11.7%. Fortinet earned this margin gain by holding spending down, and it came despite the weaker hardware margin.
• Cash conversion is strong. Operating cash flow was $946.0 million against $635.5 million of net income. For nine months it was $3.07 billion vs. $1.78 billion. The main reason is $817.8 million of deferred revenue: customers paying up front for multi-year subscriptions. Free cash flow of $864.8 million already excludes the $17.0 million escrow cash.
• Guidance mix. The full-year revenue range went up by $70 million at the midpoint, but the service revenue range went down by $40 million (to $5.150–5.170B from $5.180–5.220B). So the implied hardware forecast rose by about $110 million. Expectations are shifting toward the lower-margin part of the business.

On balance the quarter is flattered: operating income up 29% is a real result, but GAAP EPS up 39% also depends on a tax rate 4.5 points lower and a $17.0 million one-off gain. The company's own adjusted EPS growth of 23% is the better guide to the underlying trend.

Did last time's read hold up?

Our Q2 2026 report named three things to watch:

1. Would product growth hold once price increases are in the year-ago comparison? Partly. It slowed from 52% to 37%, and product revenue dipped slightly from Q2.
2. Would memory-chip costs and the $1.67 billion of purchase commitments squeeze product margins, as the 10-Q warned? Yes. Product gross margin fell 5.4 points from Q2 to 64.4%, and inventory kept climbing.
3. Would subscription growth speed up as this year's hardware installs start renewing? Not yet. Service growth slowed to 12.7%, and management cut its full-year service revenue range.

We also noted that Q2's Q3 revenue midpoint ($2.055B) was flat with Q2. Revenue came in at $2.078 billion: above that midpoint but inside the range, not above its top as in the first two quarters. Non-GAAP EPS of $0.91 did beat the $0.83–0.87 range. And the buyback pause we flagged continued through Q3.

Guidance

From the earnings release, with the July 29 ranges for comparison:

The release describes the new revenue range as 20% year-over-year growth. This is the third time this year Fortinet has raised its billings guidance. For Q4 2026 it expects revenue of $2.155–2.245 billion, billings of $2.775–2.925 billion, non-GAAP gross margin of 78–80%, non-GAAP operating margin of 35.5–37.5%, and non-GAAP EPS of $0.93–0.95 on 741–745 million diluted shares.

Outlook

Subtracting the nine-month figures from the full-year ranges gives implied Q4 service revenue of about $1.36–1.38 billion, roughly 3–5% above Q3's $1.31 billion. Q4 revenue at the midpoint ($2.20B) would leave about $830 million for product, above any quarter so far this year. That means management expects the hardware wave to keep going through year-end. The Q4 gross margin guide, meanwhile, says it expects to keep less from each sale. Three things to watch when the 10-Q arrives and in Q4:

1. What the 10-Q says caused the product margin drop. If it's memory and component costs, ask whether more price increases can offset them. If it's mix, such as lower-priced entry models or large AI-infrastructure deals, the margin may not come back.
2. Service revenue growth. Watch whether it holds above 12% or keeps drifting down. Service is about 63% of revenue and earns 87% gross margins. A trimmed service guide in a year of record hardware shipments is the one figure in this release that cuts against the upgrade story.
3. Q4 billings of $2.775–2.925 billion. This is the seasonal year-end peak. Hitting the range would confirm that customers are still signing multi-year renewals at the pace deferred revenue implies.

With $2 billion of buyback room, $4.8 billion of cash and short-term investments against $497 million of debt, and no Q3 repurchases, buybacks could support EPS again if Fortinet resumes them. Until it does, the lower share count won't keep pushing EPS growth above net income growth.