F5 tumbles as Chinese security breach weighs on guidance

[F5 Networks corporate headquarters in Silicon Valley]
Sundry Photography

F5 (NASDAQ:FFIV [https://seekingalpha.com/symbol/FFIV]) shares tumbled more than 10% in extended trading on Monday after the networking company offered up weaker-than-expected guidance for fiscal 2026, amid its recent security breach [https://seekingalpha.com/news/4505456-chinese-linked-hackers-breached-f5-networks-for-months-u-s-and-u-k-issue-warnings] linked to Chinese hackers.

Looking to the first-quarter of fiscal 2026, F5 expects to earn between $3.35 and $3.85 per share on an adjusted basis, well below the $4.04 estimate. Sales are forecast to be between $730M and $780M, below the $793.91M estimate.

“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 a statement.

For the full-year, F5 expects to earn between $14.50 and $15.50 per share, well below the $16.25 per share estimate.

The weak guidance comes on the back of stronger-than-expected results for the fiscal fourth-quarter. For the period ending Sept. 30, F5 said it earned an adjusted $4.39 per share, above the $3.97 per share estimate. Revenue rose 8.5% year-over-year to $810.09M, above the $794.86M estimate.

“Following the recent security incident, our immediate priority remains supporting customers as they evaluate and safeguard their environments,” CEO and President François Locoh-Donou said in a statement. “We are raising the bar on security across all aspects of our business. We are committed to learning from this incident, sharing our insights with customers and peers, and driving collaborative innovation to strengthen the protection of critical infrastructure.”

In addition to the quarterly results, F5 said Locoh-Donou will replace Al Higginson as the company's Chairman of the Board, starting in March 2026. Higginson leaves the company after having served on its board of directors for nearly 30 years and 20 years as its Chairman.

The company will hold a conference call at 4:30 p.m. EST to discuss the results.

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