In Q4'25, Rivian Inc.'s (RIVN) operating expenses totaled $953M USD, with R&D expenses at $424M USD and SG&A expenses at $529M USD, reflecting a slight moderation from the prior quarter's elevated spending. From Q1'23 to Q4'25, total operating expenses exhibited volatility, peaking at approximately $982M USD in Q3'25 driven by rising SG&A costs to $554M USD amid expansion efforts, while R&D expenses declined sharply from $496M USD in Q1'23 to a low of $350M USD in Q3'24 before rebounding to $424M USD; overall, SG&A has shown steady growth from $402M USD, consistently comprising over 50% of the total, indicating a shift toward administrative scaling in this EV manufacturer's cost structure.