Price Bump is a way to enable publishers to maximize their potential earnings on currently sold ad spots.
When an advertiser purchases an ad spot, they have the ability to renew the ad for an unlimited amount of time based off the original purchase price. While this is a fantastic feature for both advertiser, and publisher, it meant that as the spot grew in value, and size, the price was locked into the original purchase price.
Price Bump now enables publishers to request the advertiser purchase the spot at the new market price. The advertiser then has the option to either let the ad expire, or re purchase at the new market price.