Open Auction vs. Preferred Deal: Does Paying Less Really Get You More?

In programmatic advertising, CPM is often a deciding factor when planning media buys.

We regularly hear agencies say they prefer open auctions because of the reach they offer and, more importantly, their lower CPMs.

And we understand why. But when we ask how they make sure they're reaching French-speaking audiences in Quebec, the answer is often the same: "It's usually not an issue."

At M32 Connect, we wanted to put that assumption to the test.

Two Identical Campaigns, Two Buying Methods

For our study, we launched two campaigns using the same creatives, the same $2,000 budget, the same geographic targeting, and the same frequency cap of two impressions per day.

The first campaign ran through DV360's open auction, targeting Quebec and French-language users.

The second ran through an M32 Preferred Deal, providing direct access to our network of French-language publishers in Quebec.

Both campaigns also had a minimum viewability threshold of 60%.

Our goal was simple: compare what each approach actually delivers, beyond the CPM.

And the results were revealing.

French-Language Targeting Doesn't Guarantee Quebec French-Language Content

In the open auction campaign, only 76% of impressions were delivered on French-language content.

In other words, nearly one in four impressions appeared in environments that didn't match the language we were looking for.

And among the impressions delivered on French-language content, 13% appeared on .fr domains, associated with France rather than Quebec.

For a campaign looking to reach French-speaking Quebecers in a local context, that's a significant finding.

With M32, 100% of impressions were delivered on French-language properties based in Quebec.

This shows that geographic and language targeting alone don't necessarily guarantee the local relevance of the websites where ads appear.

What a Low CPM Doesn't Tell You

Another important finding was the quality of the advertising environments.

When reviewing the open auction results, we noticed that the majority of the ten websites delivering the most impressions were MFA (Made for Advertising) sites.

These are websites primarily designed to generate advertising revenue, often featuring high ad density and low-quality content.

In our study, these included celebrity gossip, entertainment, and gaming websites.

We excluded six MFA sites halfway through the campaign. Despite being excluded mid-campaign, those six sites still accounted for 52% of all impressions delivered by the end of the campaign.

That's a significant share of impressions going to environments that didn't meet the quality we were looking for.

By comparison, M32's top ten websites included Quebec editorial properties and regional media outlets such as Le Charlevoisien, Mon Joliette, L'actualité, and Le Nord-Côtier.

What About Performance?

The results also encouraged us to take a closer look at some of the performance metrics.

The open auction campaign delivered 1,604,106 impressions, compared to 347,829 through the M32 Preferred Deal.

That's approximately 4.6 times more impressions for the same budget.

So, in terms of volume, the open auction clearly had an advantage. But when we looked at the quality and relevance of those impressions, the picture changed.

The open auction generated an overall CTR of 0.90%, compared to 0.59% for M32.

At first glance, you might assume the open auction performed better.

However, when we analyzed the domains, we found that just ten websites, out of approximately 13,000 domains, were responsible for 54% of all clicks. Some even recorded CTRs as high as 15%.

These results, especially on MFA websites, raise questions about the quality of those interactions. An unusually high click-through rate doesn't necessarily mean users are genuinely interested in the ad.

The M32 Preferred Deal generated a CTR of 0.59% across verified editorial properties, with no MFA sites identified.

M32 also achieved 83% viewability, compared to 71% for the open auction.

A Higher CPM, But What Are You Actually Getting?

This is probably the most interesting question raised by our study.

The open auction's effective CPM was $1.25, including platform fees, compared to $5.75 for the M32 Preferred Deal.

That's a significant price difference, and we're not denying it.

But can we really compare these two CPMs without considering the environments where the impressions were delivered?

At M32, we work directly with our publisher partners and apply pricing floors to help protect the value of their inventory.

Access to quality local media has value, and that value isn't necessarily reflected in the lowest CPMs on the market.

For an advertiser looking to reach French-speaking Quebecers through local editorial environments, cost per impression shouldn't be the only consideration.

It's also important to look at where ads are appearing, whether the content is truly relevant to the target market, and how those ads are being viewed.

What We Learned

Open auctions certainly have a place in a programmatic buying strategy. They provide access to large volumes of inventory and can serve many campaign objectives.

But this study shows why it's important to look beyond CPM, especially when trying to reach a specific market like French-speaking Quebec.

With the same budget, we saw two very different outcomes. One campaign delivered significantly more impressions, but a large share appeared on MFA websites or content that didn't match the intended language. The other provided access to verified French-language properties in Quebec, with stronger ad viewability.

A lower CPM might look attractive. But it's worth making sure the impressions you're buying are actually what you need.

At M32, that's exactly what we aim to offer agencies and advertisers: direct access to quality local publishers, with greater control over where their ads appear.

Because at the end of the day, it's not just about how many impressions you buy. It's also about their quality.