This paper provides an update on the current state of in-house agencies. Whereas traditional consideration of internalizing advertising services was framed as a binary choice of build or buy, today's advertisers frequently pursue hybrid policies of build and buy to procure the customized bundle...

What accounts for the diversity and limited concentration that has long characterized the organization of the advertising agency industry? This question is addressed by treating an advertising agency as a multiproduct firm. The firm's product line or service mix is defined in terms of the set of...