An account manager is setting up assets for their Google Search campaign. They create several sitelink assets at the account level and then create more sitelinks for their campaign as well as for a particular ad group. Which sitelink assets will serve with ads?

Google Ads applies sitelink assets according to asset association level, with the most specific association taking priority for the ad that is serving. When an ad group has its own sitelinks, those are the sitelinks used for ads in that ad group. Google Ads Help explicitly notes that if ad group sitelinks are removed, the campaign-level sitelinks return, which shows the ad group level is the active serving level by default. That is why the ad group-level set serves instead of the campaign- or account-level set in this setup. Google Help+1