Google Removes Its ‘Last-Look’ Auction Advantage

The “last-look” advantage Google’s ad server gave to Google’s ad exchange so bothered publishers and exchanges that it gave rise to header bidding. As of this week, that advantage is no more, AdExchanger has learned.

Google just reworked its auction so it no longer favors itself in the allocation of bids.

A support document this week detailed the switch for Google’s Exchange Bidding in Dynamic Allocation (EBDA) feature, which is still in a beta, unfinalized state.

Google’s director of product management, Jonathan Bellack, confirmed the change to AdExchanger.

“We are collecting the price each exchange would pay, including AdX, and then putting it in a unified auction where the highest price wins,” Bellack said.

Here’s how the programmatic auction will work: All EBDA exchange participants – including Index Exchange, Rubicon Project, PubMatic, Sovrn, Smaato and Gamut – submit their final bids. The DoubleClick AdExchange (AdX) also submits its final bid. And the best price wins.

Previously, AdX would wait for all those other exchanges to submit their bids, and then give itself a chance to outbid the winner. So if Google’s exchange had two bids of $1 and $5, it would be able to beat a $4 bid from an outside exchange. Under the new auction rules, it would submit a bid of $1 (the second price) and lose the auction.

While at a glance this might seem bad for the publisher, since Google is restrained from submitting a higher bid, in fact the outcome should be the same given the rules of second-price auctions. In the above example, the impression clears at $4 regardless of which exchange takes it.

According to Index Exchange SVP of product Drew Bradstock, who had been briefed on the change, removing last-look signals a shift in how Google works with its partners.

“This is a big change in how exchange bidding works that shows they are open to having it and DFP be a lot more neutral,” said Bradstock, who spent five years at Google before joining Index Exchange. “We like that they are willing to listen and be a lot more transparent.”

During a Google forum late last year, the biggest concern voiced by publishers and exchanges centered on this last-look advantage. Bellack said feedback from those constituents influenced the decision to level the playing field.

“The exchanges and publishers we’ve been working with like this [change], because they think this is a fair way to make competition,” he said.

Google wouldn’t say how changing the auction rules will affect its win rate and revenue.

But AdX includes unique demand from AdSense and performs strongly even without its last-look edge, Bradstock said.

Google’s infrastructure is also more robust than most companies, meaning it can return more bids before the auction closes – something other exchanges and DSPs have struggled to keep up with as header bidding has multiplied the number of auctions taking place.

And Google will retain one additional advantage in the auction: It knows more about the user than it passes on to the other exchanges.

Since Google’s exchange bidding project uses a server-to-server integration, its partners can’t see as much information – think full-page URL, contextual details or viewability predictions – as they would if they had their own tag on the page.

If all buyers see the same impression, but buyers through one exchange have more information about that impression, that will be more valuable than the same impression offered up through other exchanges.

Bellack emphasized that it’s not in Google’s best interest to retain that information advantage. “We only succeed when our partners succeed,” he said.

Industry Impact

Google making its server-side auction fair moves the header bidding wars to a new chapter.

As a primer, publishers first started implementing header bidding to allow outside exchanges to compete on every impression, a privilege Google previously reserved for its own exchange. As publishers saw massive increases in yield, the trend caught like wildfire.

Technical upgrades, like moving the header bidding auction server-side, followed.

Google announced that it would allow exchanges to compete via a server-side integration last April, with its EBDA release. Index Exchange, AppNexus, and Sonobi operate server-side solutions.

And a large, outside player – Amazon – unveiled a server-side wrapper last December. Publishers could use it as an alternative to Google’s exchange bidding or other server-side solutions.

But the shift to server-side solutions, which make auctions run faster, also threaten to make the auctions lose transparency again and replicate the last-look advantage.

“It’s not clear that even the rest of server-side implementation of header bidding are operating this way,” Bellack said.

With Google removing its last-look advantage, other players with server-side solutions may feel pressured to do so too. Could ad tech enter an era where transparency, not hidden fees and rules, win the day?

“Changes to a fair auction will not be an advantage for those that aren’t open or transparent with fees,” Bradstock said.

Enjoying this content?

Sign up to be an AdExchanger Member today and get unlimited access to articles like this, plus proprietary data and research, conference discounts, on-demand access to event content, and more!

Join Today!


  1. Interesting…but doesn’t really make sense to me that a server side auction would bid 2nd prices against each other to begin with. If they now have all exchanges submit their true bid price, run a unified auction, and then price reduce across exchanges that’s a more logical approach.

    Of course, this is only in Google’s own server side wrapper for now – I wonder if they will cave to publisher pressure to play nice with other server side wrappers as well at some point, and remove this last look bias where the vast majority of the auction volume actually exists.

    Not only that, but publishers shouldn’t forget that AdX still maintains a bias against all sources of demand via EDA, where only AdX is allowed to compete against direct campaigns. Until Google ends both of these biases and starts providing real bid landscape logs from AdX that can be joined to DFP logs I think publishers are still in a sucker’s position. Auction dynamics are non-transparent by design and favor AdX revenue over the publisher.

    • Brendan

      @Ben, where did you see/hear that only AdX can compete with direct lines? Given Google created the name “EDA” to refer to AdX dynamically competing with line items based on price, wouldn’t the EBDA suggest that this practice is merely expanding to include the other demand sources Google is integrating with?

      • ADX can compete with direct sold bookings thru dynamic allocation since 3 or 4 years, maybe more.
        This is the base of programmatic guaranteed which is able to reserves blocks of inventory in DFP and where ads are trafficked in DBM.
        In a nutshell, DBM/ADX/DFP is a complete end to end programmatic solution.

      • Brendan

        I think you may have misunderstood my comment. Agreed that AdX allows you to compete with direct-sold line items.

      • This is what many publishers have told me, as confirmed through DFP support reps. I agree the DFP documentation on this topic and for a long time I had thought all price priority could compete via EDA but I’ve been assured that is not the case and AdX alone enjoys that advantage.

  2. Google needs to take the next step here in rebuilding trust and truly be transparent. A publisher should be able to readily see and have access to the server logs of every impression, and the bids and bidders, response times (and yes winners). Transparency is the solution here to rebuilding trust, not simply saying “Trust us, we fixed it on the back end”. Google was the impetus for header bidding’s evolution and have been behind this curve all along, but Google has a chance to lead here.

  3. Louis Ocus

    If EBDA were transparent on fees (who is charging what, is it equitable to all players?) and if it were transparent on auctions (who has access to what auctions), it would simply be the end of every other server-side header bidder (why would index, prebid, etc need to exist?). Google just keeps the door open for these guys by not being transparent.

  4. And then Google/DFP will still be charging the 3rd party exchanges /SSPs the fee for attending the auction? Isn’t that a hidden fee too?

  5. Google needs to be transparent here as Amazon and other big names are capitalizing on lack of trust and transparency to build alternative to Adx