Fractional CMO vs B2B Marketing Agency: Which Is Right for You?

Fractional CMO or B2B marketing agency? It's the most common structural decision growing UK B2B businesses face. The honest answer is: they solve different problems, and the best businesses often use both.

What a fractional CMO actually does

A fractional CMO is a senior marketing leader who works with you part-time — typically 1–2 days a week. Their job is to set strategy, build the marketing function, hire and manage the team, oversee agencies and budget, and report into the leadership team. They're a leader, not a doer.

What a B2B marketing agency actually delivers

An agency is a delivery team. They produce the brand, the website, the content, the campaigns, the design, the development. Strategy can be part of the engagement, but the bulk of the value is execution at a higher quality and faster pace than an in-house team can match alone.

The cost comparison

A UK fractional CMO at 1–2 days a week: £5k–£12k/month. A B2B marketing agency retainer: £8k–£20k/month. A fractional CMO plus an agency: £15k–£25k/month combined — comparable to a single full-time senior marketing hire (£140k all-in = £12k/month) but with delivery capacity layered on top.

When to choose a fractional CMO

When to choose an agency

When to use both

The most powerful combination — and the model Potent runs with several clients — is a fractional CMO holding the strategy and the agency executing against it. The CMO sets direction, the agency builds the assets, the in-house team runs day-to-day. Three layers, one accountable strategy.

Decision framework by business stage

Potent works in both models — as a B2B marketing agency, as a fractional CMO partnership, or as both layered together.