In Q3'26, KLAC's operating expenses reached $679.9M, comprising $388.8M in R&D expenses and $291.1M in SG&A expenses, marking a notable increase from prior quarters and reflecting sustained investment in innovation and operations. Over the period from Q4'23 to Q3'26, total operating expenses exhibited a steady upward trend, rising from $567.9M to $679.9M, driven primarily by R&D expenses which grew consistently from $317.1M to $388.8M with minor fluctuations, while SG&A expenses increased more gradually from $250.9M to $291.1M, showing occasional dips such as in Q3'25. This pattern underscores escalating cost pressures in a stacked bar chart format, with R&D consistently dominating as the larger component, highlighting KLAC's focus on research amid overall expense growth of approximately 20%.