Today, understanding the true return on investment from marketing efforts is more important than ever. To help marketers make smarter, data-driven budget decisions, Google has introduced significant updates to Meridian, its open-source Marketing Mix Model (MMM). These enhancements enable more accurate measurement of marketing performance and better allocation of resources. Meridian now supports the inclusion of non-media variables such as pricing changes and promotional activities, allowing businesses to more precisely assess how these factors influence sales. This provides a more complete picture of what’s driving revenue beyond just media spend. New channel-level contribution priors empower users to incorporate their own business expertise directly into the model, guiding the analysis with real-world insights and resulting in more actionable and relevant outcomes. This customization helps teams align the model with their unique market dynamics and strategic goals. The platform also now captures the long-term impact of upper-funnel marketing efforts by accounting for delayed purchase behavior. Enhanced binomial adstock decay functions model how brand awareness and media influence persist over time, delivering a clearer view of how early-stage campaigns contribute to sales weeks or even months later. Additionally, new marginal ROI (mROI) based priors help identify where the next dollar of investment will yield the highest return. These tools allow for strategic budget adjustments based on historical performance, enabling smarter, forward-looking decisions. With 30 new certified global partners and an active Discord community, Meridian users now have expanded access to expert support. These resources help organizations deploy the model effectively and turn data insights into tangible business growth.