A hard-floor price, also known as a fixed-floor price or a minimum price, is a term used in the context of online advertising to refer to the minimum price that an advertiser is willing to pay for an ad impression. A hard-floor price is set by the advertiser, and is used to ensure that their ads are not shown at a price that is lower than their desired minimum. A hard-floor price is often used in conjunction with other pricing models, such as cost-per-click (CPC) or cost-per-action (CPA), and is typically enforced through the use of bidding algorithms or real-time bidding. A hard-floor price can be a useful tool for advertisers, as it can help them to maximize the value of their ad spend and to avoid undervaluation or fraud in the ad market.