F5 stock plunges 20% as AI security spending spooks investors

F5 shares fell about 20% after the company beat estimates but guided to slower growth and higher spending on AI security. Revenue rose 13% to $917 million in the fiscal fourth quarter, while adjusted EPS of $4.42 topped forecasts; about $5 billion in market value was erased.

• Q4 revenue rose 13% to $917 million; adjusted EPS of $4.42 beat estimates
• Fiscal 2027 revenue growth guided to 8–9%, down from 11% this year
• AI-related bookings topped $100 million in fiscal 2026, up about 300%
• Board authorized an additional $1.5 billion in stock buybacks