Rivian Automotive, Inc. / DE 8-K

What Happened
Rivian Automotive, Inc. filed an 8‑K (Item 5.02) disclosing that director Rose Marcario resigned from the company’s Board of Directors effective January 1, 2026. The company announced the resignation on December 17, 2025, and filed the report on December 19, 2025. Ms. Marcario will continue to serve as Chair of the Board of Trustees of the Rivian Foundation.

Key Details

• Rose Marcario announced her resignation from the Rivian Board on December 17, 2025; resignation effective January 1, 2026.
• Upon her departure, the Board size will be reduced from eight members to seven.
• The filing does not name a replacement director.
• The 8‑K was signed by Claire McDonough, Chief Financial Officer, on December 19, 2025.

Why It Matters
Board membership changes are material governance events investors track because they can affect oversight, strategy and investor confidence. This filing confirms a seat is being vacated and the board will shrink to seven members; no successor was announced in the 8‑K. For shareholders, key follow‑ups to watch are any subsequent filings announcing a new director or changes to committee assignments that could affect board expertise and governance.