We surveyed 41 CMOs in May. Thirty-two confirmed an active MMM rebuild. Of those, 28 are doing it in-house with a data scientist and a Bayesian library, not with the agency that historically owned the model.
The reason is uncomfortable for the holding companies. Once a brand has its own first-party sales data, an MMM is closer to a six-week engineering project than a six-month consulting engagement. The hard part used to be the data plumbing. The plumbing is now standard.
What we're seeing in the rebuilds: weekly cadence (not quarterly), media + non-media variables in the same model (price, distribution, weather), and a UI that lets the CFO ask 'what if' without filing a ticket.
The implication for marketers is the same one we keep writing: the role is shifting from 'I commissioned the model' to 'I operate the model.' That role is closer to the CFO than to the agency.
"Last-click died the moment iOS 14 shipped. We've been pretending otherwise for four years. The pretending is over."