oCPM

oCPM (optimised cost per mille) is a Meta and LinkedIn bid strategy in which the platform automatically adjusts impression-level bids to maximise a chosen objective (lead, conversion, link click, video view) within a target budget. The advertiser pays for impressions but the auction targets outcomes.

How oCPM differs from manual CPM

Under manual CPM, the advertiser sets a flat price for one thousand impressions and the platform serves to anyone matching the audience, optimising only for delivery. Under oCPM, the platform overrides delivery rules in real time, biasing impressions toward users whose modelled probability of completing the chosen action is highest.

Why oCPM matters in UK financial paid media

For lead-generation campaigns on Meta and LinkedIn, oCPM (selecting "Leads" or "Conversions" as the optimisation goal) materially outperforms manual bidding once the pixel has accumulated 50+ conversions per ad set per week. Typical lifts are:

• 25-45% lower CPL on Meta lead campaigns versus manual CPC bidding.
• 15-30% lower CPL on LinkedIn Lead Gen Forms once li_fat_id-backed conversion data is flowing.
• Faster learning phase exits when oCPM is paired with the Conversions API.

When not to use oCPM

oCPM struggles in two situations:

1. Cold accounts with too few historical conversions to model from - the algorithm lacks a learning signal.
2. Campaigns where the optimisation event is too far down the funnel (e.g. signed-client) and too rare to fit on platform-side.

In those cases, optimise oCPM for an upper-funnel proxy event (qualified lead) and pass the deeper event back via offline conversion tracking.

Related terms

• CPM
• CPL
• Conversions API
• Learning Phase