Northern Trail Outfitters has several business units (BUs) and each BU uses specific data extensions,...

In Marketing Cloud, if multiple BUs need access to the same data (like Product Information), the best practice is to store and manage the data extension in the top-level (Parent) BU and share it with the Child BUs using Shared Data Extensions.

This avoids duplication, ensures consistency, and simplifies data management.

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Exact Extracts from Salesforce Documentation:

Source: Salesforce Help – Shared Data Extensions

→ "Shared Data Extensions enable parent business units to share data extensions with one or more child business units for consistent access and management."

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