Did the full loop for a Senior Brand Manager role on one of their pet food lines earlier this year. Sharing because I found almost nothing useful online.
Round 1: 30 min HR screen with a recruiter. Standard fit questions. She asked about my interest in CPG specifically, not just Mars. Have an answer for that.
Round 2: 45 min with the hiring manager. A lot of STAR questions. "Tell me about a time you influenced without authority." "Describe a situation where you had to make a decision with incomplete data." Very behavioral, very Mars Principles-flavored. I got asked about Mutuality by name, which I hadn't expected.
Round 3: A presentation round. They gave me 5 days and asked me to prepare a brand recommendation for a fictional product in an adjacent category. Not Mars brand, just a scenario. 20 min present, 20 min Q&A. The Q&A was sharper than the presentation itself. They pushed back hard on my financial assumptions.
Round 4: 30 min panel with two more stakeholders. Mostly culture/values, light on technical depth.
Total elapsed: about 6 weeks from first screen to offer call. The recruiter kept me updated the whole way, which honestly surprised me after my FAANG years. Offer was verbal, then written within 3 business days.
One thing nobody warned me: they really care that you know the category. Know Nielsen/Circana data if you can. Know the retailers they sell through. Show up with a POV on the space.