How high-growth companies are structuring their growth teams

For years the question was framed as a choice: build an in-house marketing team or hire an agency. Both answers disappoint in familiar ways. A team of two or three people cannot be expert in search ads, social advertising, creative production, tracking and email all at once, and an agency without real access to the business ends up running campaigns on guesswork.

Companies that grow quickly tend to stop treating it as either-or. They keep strategy, customer knowledge and accountability for results inside the business, usually under one senior person, and buy specialist execution such as paid media, creative production and tracking from outside partners who are held to the same commercial target. The in-house team runs the system; the specialists run the channels inside it.

Getting the structure wrong is expensive twice over: you pay for capacity you do not use, and you lose months when nobody owns the result. This article sets out what to keep inside, what to buy, how the split changes as you grow, and how to close the accountability gap that undermines many mixed setups.

Why in-house versus agency is the wrong question

The useful question is not who does your marketing but who should do each part of it. Different kinds of work have different economics: some need daily contact with your product and customers, some need deep specialist skill, and some only justify a full-time person above a certain volume.

A worked example makes the economics visible. Say a capable specialist costs you around €5,000 a month including employer costs. Covering search ads, social ads, creative, tracking and email in-house would take five such people, €25,000 a month, before management time, software and the cost of replacing anyone who leaves.

If your advertising budget is €20,000 a month, most of those five would be underused, and each would be working alone with nobody to learn from. At the other extreme, outsourcing everything only works if someone inside still sets direction and judges the results. Most growing companies sit between those two points, and the skill lies in drawing the line in the right place.

What belongs inside the business

In-house people have advantages no outside partner can match: they hear customer conversations, sit close to the product and sales teams, and can act without a briefing cycle. Work that depends on those advantages should stay inside:

• Strategy and priorities stay inside, because deciding which customers, markets and offers to pursue first is a business decision, not a channel decision.
• Positioning and messaging stay inside, because what you say about yourself has to be true, and that takes first-hand knowledge of the product and its customers.
• Content that draws on knowledge only your company has, such as technical expertise, the founder's view and real customer stories, should be written or at least led from inside.
• The link with sales and product belongs inside, so that marketing works towards the sales the business needs rather than the numbers a channel happens to report.
• Accountability for results and budget must sit with someone inside who answers for the number and has the authority to move money.

Ownership has a practical side too. Your company should own every advertising account, the analytics property, the tag manager and the customer relationship management (CRM) system where enquiries and deals are recorded, with partners given access rather than holding the keys. If a partnership ends, the history, the audiences and the tracking stay with you.

What to buy from specialists

External partners bring different advantages: depth in one discipline, exposure to many accounts, and tools and skills that would not justify a full-time hire. A paid media specialist working across a dozen accounts notices patterns, such as a creative format that has stopped working or a platform change that needs a response, earlier than someone looking after a single account.

The work that usually suits outside specialists is execution that needs depth or volume. That includes running paid media on Google, Meta, LinkedIn and TikTok; producing creative in the volume paid social needs; setting up tracking that respects consent rules, such as server-side tagging and Google Consent Mode v2; analytics and reporting; and one-off projects such as a website rebuild or a marketing automation setup.

A simple test helps you draw the line. If a piece of work needs daily product knowledge and would fill most of someone's week, hire for it. If it needs deep specialist skill but fills only part of a week, or the skill changes faster than one person can keep up with, buy it.

How the structure changes as you grow

The principle stays the same as the company grows; what moves is the boundary between inside and outside. It helps to picture three stages, because each has a different first priority:

• While the owner or managing director still runs marketing personally, the first step is a single named owner of growth, even part-time. Partners without a counterpart inside tend to drift towards whatever is easiest to report.
• With one dedicated marketing lead, keep strategy, messaging and accountability inside and buy nearly all execution, so the lead spends their time directing work rather than doing all of it.
• With a small team of three to five, bring in-house the work that has become daily and product-heavy, often email, customer communications and content, while paid media, creative production and tracking usually stay with specialists.

Move a function in-house when the work has become continuous, needs constant product knowledge and would keep a person fully busy. Until then, keep buying the depth you could not hire for at your size, and review the boundary once a year rather than every time a campaign disappoints.

Giving partners what your own team already knows

Specialists can only be as good as the context they are given. A partner who sees nothing but the ad accounts will optimise for what the ad accounts show, which is clicks and platform conversions, not the customers you actually want more of.

Hand over the knowledge that normally stays inside: the margin on each product or service, the customers you would most like more of, why people buy and why they leave. Short notes from sales calls, or a monthly half hour with whoever handles sales, will teach a partner more about your market than any amount of platform data.

The obligation runs both ways. Partners need quick approvals, timely access to data and one named contact who can make decisions, so agree response times on your side as well as theirs. For the in-house lead, the job shifts from doing the work to directing it: writing clear briefs, setting priorities and choosing between competing recommendations.

The accountability gap, and how to close it

The typical failure of the mixed model is a gap between ownership and control. The in-house lead owns strategy but not the day-to-day execution, the partners control execution but not the outcome, and nobody answers for the number the managing director actually cares about. Each side has a report showing it did its job, while sales stay flat.

The fix is structural, not personal. Put these four things in writing at the start of every partnership:

• Agree one shared commercial target that both sides are judged on, such as new customers at or below an agreed cost, or qualified enquiries and the sales they lead to.
• Build a single dashboard that the in-house team and every partner see at the same time, using your own CRM or sales data rather than each platform's report.
• Write down decision rights: who can change budgets, launch or pause campaigns and approve creative, and how quickly each side has to respond.
• Fix a rhythm: a short weekly review of the numbers, a monthly look at what was learned, and a quarterly review of strategy and budget.

Look at how partners are paid as well. A fee that rises with your ad spend rewards spending more, while a fixed fee tied to clear targets rewards results; neither is wrong, but you should know which incentive you have chosen.

The best growth teams aren't in-house or agency, but a system with clear ownership, shared accountability and the right people in each role. Getting there is less about hiring and more about writing down who owns what.

The best growth teams aren't in-house or agency, but a system with clear ownership, shared accountability and the right people in each role.

Where to start

1. 1.List every marketing activity, who does it today and who is accountable for its result, and mark the gaps and overlaps.
2. 2.Agree one commercial target for marketing, and write down exactly how it is measured and from which data.
3. 3.Check that your company owns every ad account, the analytics property and the CRM, and that partners have access rather than ownership.
4. 4.Decide activity by activity what stays inside and what you buy, using the test of product knowledge against specialist depth.
5. 5.Set up one shared dashboard and a weekly half-hour review in which you and every partner look at the same numbers.