By default, Display & Video 360 optimizes your fixed CPM bids so that you'll win impressions for the lowest price possible.
However, if you need to always bid a specific CPM, or if you are concerned about accidentally bidding beneath a price floor you've established with sellers, you can opt out of optimized fixed CPM bidding.
- Navigate your partner's Basic details.
- In the “Optimized Fixed Bidding Settings” section, uncheck the boxes next to the advertisers who need to use un-optimized fixed CPM bidding. Or, to opt out all of your advertisers, uncheck the box next to "Optimize your fixed CPM bids to the impressions at the best price".
- Click Save.