Open Marketplace vs. Private Marketplace: What’s the Difference?

examples of an open marketplace ad vs private marketplace ad

The open marketplace and private marketplace are digital exchanges where publishers can sell their ad inventory to media buyers. They both leverage real-time bidding (RTB), which is essentially an instant action. 

When a user visits a website, a corresponding bid request is sent to an ad exchange, which is a digital marketplace that enables advertisers and publishers to buy and sell the ad space.

Both the open and private marketplaces leverage RTB, but beyond this they have distinct differences and purposes. They offer different methods of purchasing ad space, for various prices, and with separate benefits. 

Learn the differences between the open marketplace vs. private marketplace so you can determine which of these real-time bidding methods works best for your campaign goals. 

What is the Open Marketplace?

An open marketplace (also known as an open ad exchange) is an exchange where digital ad placements are bought and sold as part of an auction. The auction is run through real-time bidding (RTB), enabling inventory prices to be decided in real time.

Media sellers can choose to sell their inventory through an open marketplace, making it available to any media buyers using the open marketplace to purchase ad placements. 

Benefits of Open Marketplace Inventory

One major benefit of the open marketplace is that it’s the most inclusive marketplace. Small, medium, and large publishers and agencies can all take part in open exchange auctions, reaching a large amount of people, and delivering the most scale for their campaigns.

Another benefit of the open marketplace is that it’s typically the quickest and most cost-efficient way to buy media. This makes it a highly efficient way for advertisers to get their campaigns live.   

The open marketplace leverages programmatic, which uses automated technology, AI, and machine learning. This is extremely beneficial to advertisers because it enables them to reach the right users in a scalable, flexible, and transparent way. 

What is the Private Marketplace?

The private marketplace (PMP) is another method for programmatic inventory to be sold and purchased. PMPs are a subset of real-time bidding, but allow a publisher to offer their premium inventory to a selected, limited audience of media buyers. 

What is Premium Ad Inventory? 

Premium ad inventory is ad space that a publisher has reserved for select advertisers, at a set price. It’s typically the best, most sought after ad space that a publisher has available. This ad space could be the pre-roll for an audio playlist, or the above-the-fold banner ads on a website. 

Benefits of PMP Deals

PMP deals combine the benefits of programmatic with the exclusivity of direct deals. These deals benefit the publishers who want to get top dollar for their premium space, and for digital marketers who want to place their ads on premium space. 

Just like the open marketplace, the PMP marketplace leverages programmatic, which uses automated technology, AI, and machine learning to reach the right users in a scalable, flexible, transparent way. 

PMP vs. Open Marketplace: Which is Better? 

Both types of deals come with the benefits and efficiency of programmatic. Choosing between the open marketplace and private deals will depend on your campaign goals and budget. 

The open marketplace provides you with access to the largest audience, and in a cost-effective way. If your campaign goals are to reach a broad, new audience, and to drive brand awareness, the open marketplace is a great option. 

The private marketplace is more expensive, but will deliver you access to premium, more exclusive inventory. This is a good option if you have a larger budget, or are trying to reach a highly specific audience.  

Open Marketplace vs. PMP F.A.Q. 

What is the difference between PMP and open exchange?

Open exchanges are public real-time bidding auctions that are open to all buyers and sellers. The private marketplace (PMP) is defined as an auction with a select, limited audience of advertisers chosen by the publisher. 

What does PMP stand for? 

In programmatic advertising, PMP is an acronym for private marketplace, which is a digital marketplace where select media buyers can purchase premium inventory. 

What are the 4 types of programmatic inventory?

There are several types of programmatic inventory that can be sold and purchased within the programmatic landscape. The four most common ways are through the open marketplace, private marketplace (PMP), preferred deals, and programmatic guaranteed deals.

Want to run exceptional programmatic campaigns? Request a demo to learn more about StackAdapt.

Erin Hynes
Erin Hynes

Content Marketing Manager


Erin is a content marketer with experience crafting thought-provoking content that drives awareness and supports customer acquisition. She is also a travel writer and podcaster in the tourism space.