In Q1'26, Rivian Inc.'s (RIVN) operating expenses totaled $1B USD, with R&D expenses at $458M USD and SG&A expenses at $542M USD, reflecting a modest quarterly increase from Q4'25's $953M USD combined figure. Over the period from Q2'23 to Q1'26, total operating expenses exhibited volatility with an overall upward trend, rising from $873M USD in Q2'23 to $1B USD in Q1'26, driven primarily by steady growth in SG&A expenses (from $429M USD to $542M USD) amid fluctuating R&D costs that peaked at $529M USD in Q3'23 before stabilizing around $400M-$450M USD in recent quarters; notable declines occurred in mid-2024 (e.g., R&D dropping to $350M USD in Q3'24), followed by consistent recovery, highlighting potential cost optimization efforts in R&D juxtaposed with expanding administrative overhead.