Compare · 10 min read
Fractional CMO vs Agency: which one your B2B business actually needs
Two of the most common questions a B2B founder asks at the £2m to £30m stage. They sound similar. They solve different problems. Picking the wrong one wastes a year and a budget you usually do not get a second swing at.
The short answer
A fractional CMO embeds inside your team part-time as senior marketing leadership. An agency runs campaigns or projects from the outside. Hire a fractional CMO when you need strategy and execution led from inside. Hire an agency when you need delivery capacity on a defined brief.
The side-by-side
| Fractional CMO | Agency | |
|---|---|---|
| Who it's for | Founders and CEOs who need senior marketing leadership inside the team but cannot justify a full-time CMO yet. | Teams with a clear brief, a working strategy, and a need for delivery capacity in a specific channel or project. |
| Scope | Owns the function. Strategy, hiring, budget, agency selection, messaging, accountability for the number. | Owns the brief. Campaigns, content, paid media, design, web build, or whatever the contract names. |
| Typical UK cost | £4,000 to £12,000 per month for 2 to 4 days a week. Most settle £6,000 to £9,000. | £3,000 to £25,000+ per month depending on channel, scope, and team size on the account. |
| Time to value | First 30 days for diagnosis and decisions. First 90 days for the function to look different. | First 30 to 60 days to produce. First 90 to 180 days to see channel impact at any scale. |
| Risks | Wrong person at the wrong stage. Too senior for a team that needs hands. Too junior for a function that needs leadership. | Great delivery inside a wrong strategy. Black-box reporting. Channel-specific tunnel vision. |
| When to choose it | When the missing piece is leadership and decisions, not capacity. | When the missing piece is capacity and craft on a defined brief, and someone senior already owns the strategy. |
What a fractional CMO actually does
A fractional CMO is a senior marketing leader who embeds inside your business part-time, usually two to four days a week. They are not a consultant who sends decks. They are an operator who runs the function.
In a normal week, that looks like:
- Owning the marketing strategy and the number it serves.
- Sitting in the leadership team meeting as the marketing voice in the room.
- Writing or commissioning the messaging the rest of the business uses.
- Hiring, line-managing, and developing the in-house team.
- Picking the agencies, briefing them, and holding them accountable.
- Building the reporting the CEO can trust.
The argument for hiring one is not really about money. It is about getting senior judgement in the room before the team is big enough to attract a full-time CMO. For a business between £2m and £30m of revenue, two days a week of someone who has done it three times is usually worth more than five days a week of someone who is doing it for the first time.
What an agency actually does
An agency is an external supplier hired to execute a defined brief. The good ones are extraordinary at craft. Performance-marketing agencies build channels. Content agencies produce assets. Web agencies build sites. ABM agencies run plays.
What an agency is not built to do is own your strategy. They cannot. They are not in the room when the leadership team decides what the company is for next year. They do not see the product roadmap. They do not run your sales team. Asking them to set strategy is asking a builder to write the planning application.
Where agencies are at their best:
- The strategy is clear and someone senior internal owns it.
- The brief is specific enough that quality can be judged.
- The internal team can absorb what the agency delivers, not bury it.
- The reporting cadence is set by the buyer, not the supplier.
Strengths and weaknesses, honestly
Fractional CMO · strengths
- Senior decisions, made inside the team.
- Strategy and execution under one person.
- Translates leadership intent into work.
- Holds suppliers accountable.
- Cheaper than a full-time CMO at the same seniority.
Fractional CMO · weaknesses
- Cannot do five jobs at once. Capacity is finite.
- Wrong seniority match is a bad year.
- Needs an executive who actually wants leadership, not a deck.
- Does not replace specialist channel craft.
Agency · strengths
- Specialist craft at scale.
- Tooling, processes, and benchmarks across many clients.
- Can ramp capacity quickly.
- Lower commitment than a senior hire.
Agency · weaknesses
- Cannot own strategy from the outside.
- Often optimises the channel, not the business.
- Reporting can hide more than it reveals.
- Most B2B work is too long-cycle for monthly attribution dashboards.
When to choose a fractional CMO
Pick a fractional CMO when most of these are true:
- No one senior owns marketing in the business today.
- The strategy is unclear, or the strategy is clear but nobody is running to it.
- You have a small in-house team that needs leadership and direction.
- You already have an agency or two, and the work feels disconnected from the business.
- You are between £2m and £30m of revenue and a full-time CMO is twelve months early.
The fractional CMO is the bet that the missing thing is judgement, not hands.
When to choose an agency
Pick an agency when most of these are true:
- Someone senior already owns the strategy and the function.
- The brief is specific. Channel, audience, outcome, budget, timing.
- You need craft that you would not hire full-time. Paid media, video production, brand design, technical SEO.
- Your team can absorb the output, not just store it.
- You are clear about what "good" looks like and how you will measure it.
The agency is the bet that the missing thing is capacity and craft, not leadership.
The hybrid that almost always wins
In practice, the answer for most B2B businesses between £2m and £30m of revenue is not one or the other. It is both, in a specific order.
The fractional CMO comes in first. Owns the strategy. Sets the brief. Picks the agencies. Holds them accountable. The agencies stop being a black box because someone senior is on the inside translating the work back to the business.
The same agency that was treading water under a junior in-house manager will produce twice the result with a fractional CMO sitting between them and the founder. The fractional CMO is the layer that makes external suppliers worth the money.
The Sparked POV
We do both. We embed senior fractional leadership inside the team, and we run delivery against the briefs that leadership sets. That is not because we think one of the two models is wrong. It is because, in the messy middle of B2B growth, the right setup is usually one operator owning strategy and execution from inside, with specialist craft pulled in around them.
If your strategy is already clear and you only need delivery, hire an agency. If you have leadership and you only need capacity, hire an agency. If neither of those is true, get the leadership in first, then let it choose the rest. The expensive mistake is hiring an agency in place of leadership and hoping the agency will fill the gap. It almost never does.
Frequently asked questions
What is the difference between a fractional CMO and an agency?
A fractional CMO is a senior marketing leader who embeds part-time inside your team, owns strategy, and runs the function. An agency is an external supplier that executes campaigns or projects against a brief. The fractional CMO is hired to lead. The agency is hired to deliver.
How much does a fractional CMO cost in the UK?
In the UK in 2026, a fractional CMO typically costs between £4,000 and £12,000 a month depending on seniority, scope, and days per month. Most engagements settle between £6,000 and £9,000 a month for two to four days a week. That is roughly a third of a full-time CMO salary for senior leadership the team can keep.
When should I hire an agency instead of a fractional CMO?
Hire an agency when the strategy is clear, the team is in place, and you need delivery capacity on a defined brief. Agencies are strongest when the question is how to execute, not what to execute. If you do not have someone senior owning the function, an agency will run good campaigns inside the wrong strategy.
Can a fractional CMO replace a full-time CMO?
For businesses up to about £30m in revenue, often yes. The work of a CMO at that stage is mostly making clear decisions, owning the function, and running the team. A senior fractional leader covers that in two to four days a week. Beyond that scale, you usually need someone full-time inside the room every day.
Do fractional CMOs also execute, or only advise?
The good ones execute. A fractional CMO who only advises is a consultant with a different business card. The real value is leadership plus hands on the work: writing the messaging, hiring the team, picking the agency, and being accountable for the number.
Can I use a fractional CMO and an agency together?
Yes, and it is the most common setup that works. The fractional CMO owns the strategy and runs the function. The agency owns delivery on a brief the CMO sets. The fractional CMO holds the agency accountable. The agency stops being a black box. Both roles get clearer.
Cited and further reading
- The fractional CMO playbook · The Sparked Group
- Agency vs fractional CMO: the operator's view · The Sparked Group
- The cost of a deck-only strategist · The Sparked Group
- Services at The Sparked Group
- How we run growth
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