The "Official site" badge is a snippet of text shown next to the advertiser's display name. The following image shows the badge:
When official site badges show
Google displays the badge for hotel owners, direct suppliers, central reservation systems (CRS), and integration partners (IPs). The badge won't appear for Online Travel Agencies (OTAs).
Only one Hotel Ad will receive an official site badge. If a hotel owner doesn't want a CRS or IP to ever show this badge, they must reach out to the third-party advertiser to stop bidding on the hotel(s).
There's no cost to add official site badges to your campaign, it’s done automatically by Google. Clicks on your ad are charged as usual, and you're charged a click when someone clicks any element of your ad.
Just as ads in higher positions usually get more clicks and have a higher actual CPC than the ads below, ads with official site badges also often get more clicks and have a higher actual CPC. Ad extensions (including the official site badge and other callouts) are a component of Ad Rank along with your bids, quality score, and thresholds, and the context of the person’s search. During each auction, you need to pay the minimum amount necessary to hold your position and to keep the extensions you have in that position.
The incremental cost of adding the official site badge to your ads is generally lower than the incremental cost of moving up a position on the search results page. That means the badge generally helps you get more clicks for less additional money than you would spend to increase your position.