Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for consolidating content item requests for multiple content item environments. In one aspect, a method includes consolidating content item requests for two or more content item environments in a webpage. A first content item environment is a primary content item environment and the remaining content item environments are secondary content item environments. The primary content item environments issues a content item request for itself and the secondary content item environments, and owns a process that distributes the received content items for the secondary content item environments to the secondary content item environments.