Between "a bookkeeper one day a week" and "a finance director on the payroll" there is a gap that most growing businesses fall into. Turnover has reached the point where the numbers matter and decisions depend on them, but not the point where a full finance team is affordable or even sensible. An outsourced finance function fills that gap by buying the roles rather than the people.
What the function actually consists of
A finance function is not one job. It is four, stacked, and they need different skills and different hourly rates:
- Transaction processing — sales and purchase ledgers, bank reconciliation, expenses, payroll input. High volume, low judgement, the cheapest hour;
- Compliance — VAT returns, payroll filings, statutory accounts, corporation tax. Deadline-driven and rules-based;
- Management reporting — monthly accounts with commentary, budget versus actual, cash flow forecasting, KPI reporting. The first level where judgement is doing real work;
- Commercial finance — pricing, margin analysis, investment appraisal, funding, board reporting. The most valuable hour and the one a growing business buys least of.
The failure that prompts most businesses to look at outsourcing is a mismatch between those layers. Either an expensive person is doing cheap work — a qualified accountant reconciling a bank feed — or a cheap person is doing expensive work, which is how a business ends up making a pricing decision on a gross margin that was never accurate.
What it costs against the alternative
The comparison is not fee versus salary; it is fee versus total employment cost, and the total is consistently understated. On illustrative figures, a finance manager on £55,000 costs the business closer to £70,000 once employer National Insurance at 15% above £5,000, pension contributions, software licences and a desk are counted — before recruitment cost, or the months of reduced output around a departure. Two honest qualifications: those numbers are an illustration with stated assumptions rather than a market rate, and paid holiday is not an addition to the salary, because the salary already covers it. What holiday genuinely costs is cover or lost capacity during the absence, which is a separate line and a smaller one.
Outsourcing converts that into a variable cost with no recruitment risk and no single point of failure. It also buys seniority in fractions: two days a month of someone who has taken a company through a funding round, rather than a full-time hire who has not.
Where it does not win is in businesses with high transaction volumes and genuinely specific processes — a manufacturer with complex work-in-progress, or a business whose finance team is embedded in operations. There, an in-house team supported by external specialists is usually the better structure, and an honest provider will say so.
What good looks like
Three things distinguish a working arrangement from an expensive one.
A fixed monthly timetable. Management accounts by a stated working day, every month, with commentary rather than just numbers. A provider who delivers "within a few weeks of month end" is producing history, not information.
Named people. The value is in continuity — someone who knows why the margin moved in March because they were there in March. A rotating pool of processors produces accurate ledgers and no insight.
Access to the layer above. The reason to outsource rather than hire is to reach commercial finance capability at a fraction of a full-time cost. If the arrangement delivers only processing and compliance, it is bookkeeping with a longer name.
Getting the transition right
The move is a systems and documentation exercise more than a staffing one. The steps that prevent a bad first quarter: agree the chart of accounts and the reporting pack before anything moves, rather than accepting whatever the previous system produced; document the processes that are genuinely specific to the business — revenue recognition, job costing, the approval matrix; migrate with a clean cut at a period end, with balances agreed on both sides; keep parallel access to the old system for long enough to answer questions about prior years; and set the first three months' expectations deliberately, because a new provider's early output is usually slower and more question-heavy than the steady state.
Two risks deserve naming. Data access — the business must own its accounting system and data, with the provider working inside it, never the other way round. And segregation of duties: an outsourced provider preparing payments and reconciling the bank is the same control weakness it would be in-house, so payment release stays with the business.
When to bring it back in
Outsourcing is a stage, not a destination. The signals that it is time to hire: the volume of transaction processing makes the external fee uncompetitive; decisions need someone in the room daily rather than monthly; or the business has grown a genuine finance need — treasury, complex funding, multi-entity consolidation — that justifies a permanent senior hire. At that point the sensible structure usually inverts, with an in-house team and the external firm retained for the specialist work.
Acumon provides finance function support from bookkeeping through to board reporting — bookkeeping, management accounts and cloud accounting, with an interim accountant or CFO where the commercial layer is what is missing. The right question is not whether to outsource, but which of the four layers you are currently short of.