Methods, systems, and apparatus for content item auction bidding. In one aspect, a method includes receiving a request for a content item, the request including request feature values and a device identifier, the device identifier being included in a remarketing list; obtaining a predicted performance measure for a remarketing content item associated with the remarketing list based on a first timestamp and a second timestamp, the first timestamp being included in the remarketing list and associated with the device identifier included in the request, and the second timestamp being for the request; determining a bid adjustment value based on the first timestamp and the second timestamp; obtaining a remarketing bid for the remarketing content item, the remarketing bid specifying an amount a content item provider is willing to pay for distribution of the remarketing content item; and adjusting the remarketing bid based on the bid adjustment value.