Note
You can bulk share Custom and Lookalike Audiences between ad accounts and/or media agencies as long as both the sharer and recipient are tied to a Meta Business Suite. If that is not the case, first connect both in Meta Business Suite and in Smartly settings.
The benefits of sharing custom audiences:
When creating new accounts, you can still keep using the same Meta Pixels on your website;
You only have to upload seed audiences to one account; and
You can be sure that all accounts are using exactly the same audiences.
Establishing a business relationship
If you want to share Customer File Custom Audiences (that are based on email lists etc.) between different Facebook Business accounts, the businesses in question need to establish a business relationship first. Read Facebook's instructions on how to establish a business relationship.
If these two businesses have already established a relationship before, you can proceed to the next step.
Share audiences across Ad Accounts
Between accounts that belong to the same Facebook Business account, you can share your custom and lookalike audiences from one account to another in the Campaign Assets section of Smartly.
In the main navigation, click Media > Campaign Assets.
Under Custom Audiences, click View.
Select one or more audiences. You can use the search function to filter the list.
Click Share audiences.
Select one or more accounts.
Click Share.
Limitations
You can only share an audience from the account it was created in i.e. no re-sharing / "forwarding" audiences
You can only create lookalike audiences on the account for which the seed audience has originally been created. If you try to create lookalikes from a shared audience on another account, you will get an error message.