In Q4'25, Fortinet's (FTNT) operating expenses reached a total of 891.6M USD, with R&D expenses at 205M USD and SG&A expenses at 686.6M USD, marking the highest quarterly figure in the observed period and reflecting continued investment in growth areas. From Q1'23 to Q4'25, total operating expenses exhibited a steady upward trend, rising from 682.2M USD to 891.6M USD, driven primarily by escalating SG&A costs that increased 29% over the period amid expansion efforts, while R&D expenses grew 36% with notable accelerations in Q1'24 and Q2'25 before stabilizing. The stacked bar chart highlights SG&A as the dominant component, consistently comprising over 75% of total expenses, with minor fluctuations in Q1'24 and Q3'23 indicating temporary efficiencies, but no significant declines overall.