In Q4'25, Monolithic Power Systems' (MPWR) operating expenses reached $214.33M USD, with R&D expenses at $95.60M USD and SG&A expenses at $118.73M USD, marking a slight quarterly decline in R&D but continued growth in SG&A. From Q1'23 to Q4'25, total operating expenses exhibited a strong upward trend, rising from $134.50M USD to $214.33M USD, driven primarily by consistent increases in both R&D (from $63.71M USD to $95.60M USD) and SG&A (from $70.80M USD to $118.73M USD). Notable acceleration occurred in 2024 and 2025, with SG&A showing particularly robust growth—peaking at $118.73M USD—while R&D remained relatively stable in the final quarter after steady climbs; this stacked bar chart highlights SG&A as the dominant component, comprising over 55% of total expenses by Q4'25.