Glossary
What is campaign budget optimisation (CBO) on Reddit Ads?
Melvin Salas1 min readVerified 11 November 2026
Short answer
Campaign budget optimisation, or CBO, is a Reddit Ads feature that Reddit says automates budget allocation across ad groups. Advertisers set budgets and bids at the campaign level, while automated optimisation shifts spend toward the best-performing ad groups, without the advertiser manually adjusting spend across ad groups.
Reddit says it is now available on the Awareness and consideration and Traffic objectives, and in beta on Sales, Lead generation and App promotion. Its figure is that advertisers using CBO for traffic saw 10% lower CPCs, from a Reddit internal study in Q4 2025.
The announcement does not say how Reddit decides which ad groups are best-performing, so we do not state it.
Our reading, not Reddit's: a lower cost per click is not a lower cost per customer, and moving budget between ad groups ends any even split you set up to compare them. While ad groups are a test, we keep their budgets separate. Once the CRM shows which ones produce customers, CBO is a reasonable way to let Reddit do the allocating.
Nothing that moves money happens without evidence
At Riibon a bid or budget change starts from the platform's own forecast and the account's history, and no change that touches money goes live without a person signing it off. Every change is written down with what happened after it, so the next decision starts from the last one.
Ask the Riibon app what changed in your account before your numbers moved. Access starts with a short call: we look at your ads together, then run them for you or set the app up with you.