Optimized CPM (oCPM)

Optimized CPM is a Reddit bidding mode that bills per impression but delivers toward the people most likely to complete your chosen conversion.

You still pay on a per-thousand-impression basis, but instead of buying impressions flat, Reddit uses your Pixel and Conversions API signal to predict who is likely to convert and shows your ad to them. You give it a conversion event to chase, and it weights delivery toward accounts that resemble your past converters. It sits between raw CPM and paying strictly per action.

You run a signup campaign on oCPM with Complete Registration as the event. Reddit reads who signed up before and pushes impressions toward similar users. Your raw CPM may read higher than a flat reach buy, but your cost per signup drops because the impressions land on better people.

oCPM is blind without conversion signal. If your Pixel is not firing the event, or volume is thin, the model has nothing to optimize toward and delivery drifts back to generic. Confirm the event is tracking and getting enough conversions before you trust the mode to spend for you.

It optimizes toward a signal. No signal, no optimization.