The exchange model rumbles along gathering momentum with each passing week. The front runners of the new model are gaining traction in the market. Big brand advertisers now demand a better return on their marketing spend. It is for this reason that the CPA model is in vogue with all marketers and advertisers. Exchanges offer value and accountability. The buyer side is exciting by the prospect.

But some large publishers are still not totally convinced. They want a better price for their inventory, and they still believe remnant exchanges offer little value. With the help of yield optimising tools, from the likes of Admeld, Yieldex, and Rubicon Project, publishers are taking more control of their inventory and the price being paid.

One company looking to help big publishers - those generating upwards of 400 million page impressions per month - maximise the value of their inventory is Amsterdam-based Improve Digital. Their CMX (Controlled Media Exchange) platform leans heavily on the exchange model, but is only open to invited buyers. Publishers put unsold advertising space onto the CMX platform, allowing invited advertisers, marketers and agencies to bid for this inventory.

It might fly in the face of the open exchange model, but there is genuine concern among publishers about the “cannibalisation” of their inventory. Why should an advertiser pay £40 CPM for a premium spot when they can pick up non-guaranteed inventory on the same site for a fraction of the cost from an ad network or ad exchange? The publisher does afterall supply the audience for the media buyer.

By having a closed exchange, publishers can demand a floor price for their inventory and invite the advertisers and media agencies they want on their platform.

For the buyer, CMX allows access to secure and, more importantly, premium inventory. This should allow the CMX platform to become part of the bigger exchange eco system. It might even actually go some way to addressing the availability of premium inventory. Why shouldn’t a performance-based media buyer like MediaMath or Infectious Digital buy across the closed media exchanges of massive publishers like the New York Times? They can simply plug-in to the closed exchanges and buy the premium inventory required for their clients.

Improve Digital’s CMX has attracted a lot of interest from big digital media companies in the UK, Europe and the US, as they look to venture into the exchange marketplace. The platform is a compelling proposition for large scale publishers, and will definitely raise the profile of the exchange model.