Abstract: A method for budget distribution in online advertising, the method comprising using at least one hardware processor for: receiving a definition of a single advertiser budget to be spent on advertising multiple ad entities in an online advertising platform; receiving historical performance data associated with the multiple ad entities, wherein the historical performance data comprises multiple proportional performance metrics for each of the multiple ad entities; computing a health index for each of the multiple ad entities, the health index being a weighted average of multiple components comprising the multiple proportional performance metrics, wherein the multiple components are each monotonic with respect to spend; and proportionally distributing the single advertiser budget between the multiple ad entities, based on the health indices of the multiple ad entities.