Yet another perk has been added to Managed Accounts by Google – the ability to create and share negative keyword lists across accounts.
Remember when you would have to laboriously add the same lists of negative keyword accounts manually or using a script to automate cross-account negative lists? Well, not anymore. For any accounts in a managed account, it’s possible to set up a negative keyword list in the top-level Share Library that can then be associated at the account level.
After creating a manager account -level negative keyword list, you just have to apply it to campaigns at the individual account. Manager account-level lists will show up in the Shared Library of every account that is labeled with “Shared from a manager account.” As with any other list found in the Shared Library, click the check box next to it to apply it to campaigns within that account.
For more details, see the AdWords support page.