If you win 100% of impressions bid (i.e., impressions bid equals impressions won), you have not necessarily reached the maximum number of impressions available overall.
The 'Impressions Bid' column displays the number of impressions that your specific campaign is bidding on that match your campaign targeting criteria. Impressions Bid takes into consideration many factors, including the geographic location you are targeting, the banner sizes you are using, contextual targeting, audience targeting, device targeting, and every other filter you can apply to a campaign.
The 'Impressions Won' column is displaying the amount of impressions bid that you have won. This is determined largely by your bid CPM.
If you alter your targeting criteria (e.g., raise your CPM bid, add more sites, add more ad dimensions, or change frequency cap), you may have the opportunity to win additional impressions.
There are several things you can do to increase the number of impressions that your campaign is buying:
- Consider raising the bid to compete for more of the site’s available volume.
- Ensure that you are not hitting your campaign budget -- if so, raise it.
- Raising your frequency cap will also ensure you win more impressions (showing ads more frequently to a user can result in higher CTR, or more visibility at the very least.)
- Ensure you are using every ad size that the site has available.
- Consider adding more sites to your campaign.
- Speak with your account manager about opening up new sites for you, or arranging Private Marketplace deals with publishers for more traffic.
- Loosen location targeting (choose a larger region)
- Loosen device/browser/OS targeting
- Open up day parting, if enabled
- If it's a contextual or audience campaign, try adding more segments, categories or reducing the "relevance" required (classic UI only)
- Turn off "Deliver the budget evenly throughout the day". If the targeting settings constrain the campaign to a very narrow number of bid opportunities, its important to be bidding on every opportunity possible.