An advertiser is running a conversion campaign that utilizes both prospecting and retargeting tactics. After two weeks of delivery, 90% of spend has been delivered against the prospecting ad group. Which action should the advertiser take to improve retargeting performance?

Separating retargeting and prospecting into different campaigns allows for independent budget allocation and optimization. When combined, prospecting often consumes the majority of the budget due to its broader audience, leaving insufficient spend for retargeting, as seen in this scenario where 90% went to prospecting. Uploading a customer list is a good retargeting strategy but doesn't address the budget imbalance. Creating a catalog sales campaign is a specific campaign type, not a general solution for budget allocation between prospecting and retargeting. Retargeting the prospecting audience is already part of the strategy; the issue is the spend distribution, not the audience definition.