I a trying to understand the relationship between All Subscribers, Business Units and Business Unit Filters and how exactly the BU filter is applied. From my understanding, the BU Filter controls if a given BU can access a subscriber in the All Subscribers table in that BU. My BU unsubscribe setting are set to unsub from each BU, not the Enterprise account. I do realize that there is only one true All Subscribers Table for a given account and BU's actually have a hidden status field.


Let's say I'm using a Data Extensions to import new subscribers into child BU-1, and there is a BU filter on BU-1 that is a true or false value i.e. BU-1 == 'true'. If I import these new subscribers through a data extension and try to send them an email, will the send process evaluate if they meet that subscriber filter on send, or will the email still be sent to those subscribers, then they'll join the All Subscribers table.

My follow up question would be in that scenario, would I then need to run an automation to update the field value of each subscriber in the All Subscriber's table, such that they will satisfy the BU Filter condition i.e. BU-1 == 'true'.

I am in the process of setting up multiple BU's and wondering if the BU filter is actually used as a 'send permission' or status value for each BU, or if it's more of a UI tool so that marketers can't see data from other subscribers not belonging to the BU they work in.

Thanks and any clarification is helpful!

1 Answer 1


Subscribers are owned by the parent. Subscribers have an active delivery status upon first send in a business unit. Any opt-opt outs are recorded in a hidden system data view per business unit. The All Subscribers view is filtered (presumably) using this hidden data set.

If you want to maintain true business unit subscriber status, you can do what's described here with an Automation in the parent BU: https://sprignaturemoves.com/determining-business-unit-subscriber-status/

Summarizing the queries in the above post:

  1. A query that creates a row for every subscriber in every business unit. Since subscribers exist at the enterprise level, they could potentially have a send (or unsubscribe) in any child business unit.

  2. A query that sets the status for the subscriber if an explicit unsubscribe in a business unit has been recorded.

You can create whatever form of business unit membership that's appropriate for your scenario, but the above is my understanding of the underlying data.

  • Appreciate the help! If you don't mind me clarifying, then what is the purpose of the BU Filter in relation to the send status of a business unit, or is it purely a UI filter? Since based on your response above, it wouldn't matter if the subscriber satisfies the filter on the first send, they'll automatically get a subscribed hidden status to that business unit.
    – Tazzy1234
    Oct 24, 2023 at 16:49
  • As far as I know, the BU filter is only for masking subscribers from users. Oct 24, 2023 at 17:39

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