Campaign Budget Optimization (CBO) is a Meta Ads feature that distributes a campaign’s budget across ad sets on its own, steering more money to where results are better. It takes manual money-shifting off the advertiser’s hands and usually raises efficiency, provided the goal and conversions are well defined. The cost is less control over how much goes to a particular group: the algorithm may almost skip a set it judges weaker. (Compare: Bid Strategy, Daily budget)