Shares in F5 Inc. fell more than 6% in late trading today after the application security firm reported earnings and revenue beats but gave weaker-than-expected guidance following a security breach in October.

For its fourth quarter that ended on Sept. 30, F5 reported adjusted earnings per share of $4.39, up from $3.67 in the same quarter of the previous fiscal year, on revenue of $810 million, up 8% year-over-year. Both figures were ahead of the $3.97 per share and revenue of $794.86 million expected by analysts.

F5 saw systems revenue in the quarter of $185 million, up an impressive 42% year-over-year, while software revenue was up 0nly 0.3% year-over-year, to $229 million. Rounding out the revenue figures, the company’s global services revenue came in at $396 million, up 2% year-over-year.

Business highlights in the quarter included F5 announcing two acquisitions — MantisNet in August and Calypso AI Inc. in September.

MantisNet offers cloud-native network observability software designed to simplify the process of accessing and extracting network intelligence in real time. F5 plans to integrate the company’s capabilities into the F5 Application Delivery and Security Platform to allow organizations to confidently transition to cloud-native architectures while maintaining deep operational visibility, automation and security.

CalypsoAI, which F5 acquired for $180 million, offers a cybersecurity toolkit called the Inference Platform that is optimized to protect AI workloads. F5 plans to integrate the Inference Platform into the F5 Application Delivery and Security Platform to complement the existing cybersecurity features in the bundle.

“Our strong fourth-quarter results cap an exceptional year where we grew revenue 10% while driving 18% non-GAAP earnings growth,” Chief Executive François Locoh-Donou said in the company’s earnings release.

After the end of the quarter, on Oct. 15, F5 disclosed in a filing with the U.S. Securities and Exchange Commission that a sophisticated nation-state threat actor had gained unauthorized access to internal systems and stolen portions of the source code for its BIG-IP platform along with undisclosed vulnerability information.

The breach itself did, however, occur in the company’s fourth quarter, having been detected on Aug. 9. Whether F5 was at fault or not, the breach will affect the company’s earnings for the first half of its 2026 fiscal year.

“While demand drivers and the company’s current pipeline support mid-single-digit revenue growth in fiscal year 2026 against its exceptional 10% growth in fiscal year 2025, F5 anticipates some near-term disruption to sales cycles as customers focus on assessing and remediating their environments following the recent security incident,” the company said in its earnings release. “Taking this into account, for fiscal year 2026, F5 is guiding to total revenue growth of 0% to 4%, with any demand impacts expected to be more pronounced in the first half, before normalizing in the second half of fiscal year 2026.”

For its fiscal 2026 first quarter, F5 expects adjusted earnings per share of $3.35 to $3.85 per share on revenue of $730 million to $780 million, while for the full year, F5 expects adjusted earnings of $14.50 to $15.50 per share.

Photo: F5