Outsourced Accounting for Startups: Building a Finance Function Before You Can Fund One

Introduction

Eighteen months after incorporation, a SaaS founder sits down with an investor’s due diligence team to close a £1.5m seed round. The product is strong and the revenue chart points the right way. Then the questions start.

Why are there 140 entries in the director’s loan account? Which of these card payments were for the business? Why is a year of upfront subscription income all in one month? And where are the timesheets behind last year’s R&D claim?

The round doesn’t collapse. But it slows by six weeks, the lawyers add warranties, and the valuation conversation gets harder.

None of that was caused by bad accounting. It was caused by almost no accounting in the first year, when nobody thought it mattered yet.

Most writing about outsourcing accounting services for small business assumes a stable company with predictable needs. Startups are different. They don’t need a full finance department on day one, and they can’t afford one. What they need is the right piece of the finance function at the right moment.

This guide is for founders in their first two years, and for UK accountancy practices with startup portfolios who want a practical way to scope the work.

Three changes make it more pressing this year:

• For accounting periods beginning on or after 1 January 2026, FRS 102 brings in a new five-step revenue model, which matters for every subscription business.
• The EMI share option regime was widened from 6 April 2026.
• The section 455 charge on overdrawn director’s loans rose to 35.75% on loans made from that date.

What follows takes the finance function stage by stage: the foundations in months 1–6, the reporting layer in months 6–18, the statutory layer from month 18, the three habits that cost startups most, and what due diligence will ask to see.

The startup finance roadmap at a glance

Stage	Months	What the finance function must do	What goes wrong if it doesn’t
Foundations	1–6	Bank feeds, chart of accounts, founder payroll, VAT decision, Companies House and HMRC registrations	Mixed spending, informal director’s loans, missed registrations
Reporting	6–18	Monthly management accounts, runway, revenue recognition, R&D records, option records	Lumpy P&L, surprise cash gaps, weak R&D claims, failed EMI options
Statutory	18+	First statutory accounts, Corporation Tax return, board pack	Late filings, lost R&D value, a board that doesn’t trust the numbers

Months 1–6: foundations that cost almost nothing now

Bookkeeping for startups in the first six months is mostly plumbing. Get it right and every later stage is cheaper.

Clean bank feeds from the first transaction

Open a business bank account before the first invoice goes out and connect it to cloud accounting software immediately. Every payment platform the business uses needs its own feed or clearing account, whether that’s Stripe, PayPal, GoCardless or a company card.

Good startup bookkeeping comes down to making sure every pound has a source document and an obvious home.

A sensible chart of accounts

Avoid both extremes: the default template with hundreds of codes, and the habit of coding everything to “general expenses”. Separate the costs investors will ask about.

Cost category	Why investors care
Hosting and infrastructure	Drives gross margin for software businesses
Software subscriptions	A fast-growing cost that hides waste
Contractors	Shows reliance on non-employees, and matters for R&D
Salaries and payroll costs	The biggest line in most startups’ burn
Sales and marketing	Needed for customer acquisition cost
R&D-related costs	Feeds the R&D claim directly

Tag it properly now and nobody has to reconstruct it later.

Payroll for founders

Founders often take nothing for months, then start moving money informally. That’s exactly how director’s loan accounts fill up.

Decide early whether founders will draw a salary, register for PAYE before the first payday, and run it properly through RTI. With employer National Insurance at 15% since April 2025, the salary level is a real decision. It depends on National Insurance thresholds and on whether the company can claim the Employment Allowance, which generally isn’t available where the only paid employee is a director. Review it every April. Our payroll team runs director payrolls for practices across the UK.

The VAT registration decision

Registration becomes compulsory once taxable turnover passes £90,000 in any rolling 12-month period. Many startups register voluntarily well before that, and the right answer depends on who the customers are.

Take a B2B software startup spending £3,000 plus VAT a month on hosting and tools. Registering lets it recover £600 a month, or £7,200 a year, and its business customers simply reclaim the VAT it charges. There’s no price impact.

Now take a consumer app selling a £20 subscription. Once registered, £3.33 of every sale goes to HMRC, leaving £16.67, unless the price goes up. For consumer businesses, registering early is a genuine commercial decision. Make it deliberately rather than by default.

Companies House and HMRC basics

Directors now need to verify their identity with Companies House. The company must also tell HMRC it’s liable for Corporation Tax within three months of starting to trade.

Put the first accounts deadline in the diary now. For a new company it falls 21 months after incorporation.

Months 6–18: when investors start reading the numbers

Somewhere in this window the startup raises money, hires its first employees or starts selling in earnest. The finance function has to move from record-keeping to reporting.

Investor-ready management accounts

Monthly management accounts should arrive within days of month-end, not weeks. That means a profit and loss account, balance sheet and cash flow, with a short commentary on what moved and why.

Accruals and prepayments matter here, because an annual software licence paid in January belongs to twelve months, not one. Investors read a lumpy P&L as a lack of control. Our management accounts service is built around exactly this monthly rhythm.

Runway reporting

Runway is cash divided by net monthly burn, and every founder should know theirs to the month. The useful version shows it three ways.

Scenario	Cash in the bank	Net monthly burn	Runway
Current burn	£600,000	£50,000	12.0 months
Hiring plan delivered	£600,000	£65,000	9.2 months
Revenue stalls	£600,000	£72,000	8.3 months

Illustrative only. A board will forgive a short runway. It won’t forgive one nobody saw coming.

Revenue recognition for subscription income

If customers pay annually in advance, most of that cash is deferred income on the day it arrives. A customer who pays £12,000 on 1 March for a year’s subscription has given the company £1,000 of revenue by a 31 March year end. The other £11,000 is a liability.

From periods beginning on or after 1 January 2026, the revised FRS 102 Section 23 makes contract terms, bundled deals and set-up fees more important to get right, because each promise in a contract has to be identified and priced. Build the deferred income schedule monthly rather than at year-end.

R&D claim record-keeping

R&D tax relief can be worth a great deal to a tech startup, and HMRC’s scrutiny of claims has risen sharply. Two forms catch first-time claimants out:

• Claim notification: a company claiming for the first time, or after a gap of three years, must file it within six months of the end of the accounting period.
• Additional Information Form: every claim needs one, submitted before the company tax return.

Under the merged scheme, most payments to overseas contractors no longer qualify either, which matters for startups using offshore developers. The claim is only as strong as the records behind it: project dates, the technical uncertainty being tackled, who worked on what and for how long.

EMI and share option bookkeeping

Share options are how startups compete for people they can’t yet pay market rate. EMI options granted before 6 April 2027 must be notified to HMRC by 6 July after the end of the tax year of grant, or they lose their tax advantages.

The government plans to remove that separate notification for later grants. Until then, it’s one of the most common ways EMI fails.

From 6 April 2026 the regime was widened, including a £6 million company option limit and a maximum option life of 15 years. On the bookkeeping side, that means four things:

• keeping the option register in order;
• holding the HMRC-agreed valuations and board minutes;
• filing the annual employment-related securities return;
• recognising the share-based payment charge in the accounts.

Months 18 and beyond: the statutory layer

By now the company has filed, or is about to file, its first statutory accounts and Corporation Tax return. If the earlier stages were done properly, this is the easy part.

The deadlines that matter

Obligation	Deadline
Register for Corporation Tax	Within three months of starting to trade
VAT registration	Within 30 days of the end of the month turnover passes £90,000
First accounts to Companies House	21 months after incorporation
Later accounts	Nine months after the year end
Corporation Tax payment	Nine months and one day after the period end
CT600 return	Twelve months after the period end
R&D claim notification (if required)	Six months after the period end
EMI grant notification (pre-April 2027 grants) and ERS annual return	6 July after the end of the tax year

Loss-making startups still have to file. Getting losses and any R&D credit into the return correctly can make a material difference to cash. Our Corporation Tax team prepares CT600s with R&D schedules under the practice’s review.

The board pack

This is also the stage for a proper board pack: management accounts, KPIs, runway, hiring against budget, and a short narrative from the founders. It doesn’t need to be long.

It needs to arrive on time every month, built from the same numbers, so the board stops asking where the figures came from and starts asking what to do about them.

Leases and the balance sheet

If the company signs an office lease or finances equipment, note that for FRS 102 reporters, periods beginning on or after 1 January 2026 bring most leases onto the balance sheet. ACCA’s summary of the changes covers the detail. EBITDA and reported debt both rise, which investors will notice.

[Diagram suggestion: startup finance timeline · 3 stages · month 0 to month 24 with key deadlines marked. Caption: each stage builds on the one before it.]

The three habits that cost startups most at audit or due diligence

The same three problems appear in startup files again and again. None is technically difficult. All of them get more expensive the longer they’re left.

Mixed personal spending

Founders buy lunches, flights and the odd laptop on whichever card is nearest. Every personal item on the business card, and every business cost on a personal card, creates a reconciling item someone has to unpick later.

At due diligence those items look like weak controls, even when the amounts are small. The fix is simple: one business card, one personal card, and an expense claim process for the exceptions.

Undocumented director’s loans

Money moving between founders and the company without paperwork ends up as an unexplained balance on the director’s loan account. If the account is overdrawn at year-end and not repaid within nine months and a day, the company pays section 455 tax.

The rate is 35.75% on loans made on or after 6 April 2026. A £20,000 balance left unpaid means a £7,150 charge. It’s refundable once the loan is repaid, but only after a delay. Loans above £10,000 can also create a benefit-in-kind charge for the director.

Write it down: a short loan agreement, a running schedule, and a decision at each year-end about how the balance will be cleared.

No contemporaneous R&D records

Rebuilding an R&D claim a year later from Slack threads and memory is possible, but it produces a weaker claim and a nervous reviewer. HMRC wants to see what the company was trying to achieve, what was uncertain and the evidence of the work.

A ten-minute monthly habit of logging projects, staff time and key technical decisions turns a stressful annual exercise into a routine one.

What due diligence will ask to see

Investors’ accountants ask for broadly the same pack every time. A startup that can produce it in a day looks like a company that’s in control.

• Monthly management accounts for at least the last twelve months, built from reconciled books.
• A deferred income schedule that ties to the balance sheet and the customer contracts.
• A director’s loan schedule with every movement explained and agreements on file.
• The cap table and option register, with EMI notifications, valuations and board approvals.
• R&D claim files, including the claim notification, Additional Information Form and supporting records.
• VAT and PAYE history showing returns filed and paid on time.
• Leases and finance agreements, with the accounting treatment under the revised FRS 102.

Outsourcing the finance function without losing control

Outsourced accounting for startups isn’t about handing the numbers to someone else and forgetting them. It’s about getting finance-team discipline for a fraction of the cost of a finance team, while founders stay close to the figures that matter.

What founders should keep

Founders should keep:

• bank authority and payment approvals;
• pricing and hiring decisions;
• the relationship with investors.

What moves is the production: reconciliations, payroll processing, management accounts, schedules and filings.

For practices: scoping startup engagements

The same principle applies whenever practices outsource accounting for small business clients: production moves, but review, judgement and the client relationship stay with the accountant. Use the roadmap above to price each stage separately rather than quoting a single headline fee that breaks at month six.

For practices supporting technology clients, our IT and SaaS accounting team handles the stage-specific work behind the scenes: monthly closes, deferred income, R&D schedules and share scheme work.

Frequently asked questions

When should a startup hire an accountant?

Ideally at incorporation, and certainly before the first payroll run, the VAT registration decision or the first investor conversation. Early decisions about bank feeds, the chart of accounts, founder pay and share structure are cheap to get right and expensive to unpick later.

Does a UK startup legally need an accountant?

No. But a limited company has to file annual accounts and a confirmation statement with Companies House, and a Corporation Tax return with HMRC. It also has payroll and VAT submissions where relevant. Mistakes in those filings, or in R&D and EMI paperwork, can cost far more than professional fees.

How much does outsourced accounting for startups cost?

It depends on four things:

• transaction volume;
• payroll and VAT;
• R&D work;
• how much monthly reporting the company needs.

Most accountants quote a fixed monthly fee once they’ve seen the books. Be wary of a headline price that doesn’t say what’s included, particularly management accounts, R&D schedules and year-end work.

Should my startup register for VAT before it reaches £90,000?

Often, if you sell mainly to VAT-registered businesses. They reclaim the VAT you charge, and you recover VAT on your costs, including some from before registration. If you sell to consumers, registering early effectively cuts your margin or raises your prices, so the case is weaker.

What’s the difference between bookkeeping and management accounts?

Bookkeeping records every transaction accurately. Management accounts turn those records into monthly reports that founders and investors can use to make decisions, usually a P&L, balance sheet, cash flow and commentary. You need reliable bookkeeping before management accounts mean anything.

What records does a startup need to claim R&D tax relief?

Keep these as the work happens:

• project descriptions and start and end dates;
• the scientific or technological uncertainty being addressed;
• staff time on each project;
• the related costs.

First-time claimants must also file a claim notification within six months of the period end, and every claim needs an Additional Information Form before the tax return.

Do overseas contractor costs qualify for R&D relief?

Under the merged scheme, which applies to accounting periods beginning on or after 1 April 2024, most payments to overseas contractors and externally provided workers no longer qualify. There are narrow exceptions where the conditions needed for the work don’t exist in the UK. Startups using offshore developers should check their claim carefully.

When do EMI options have to be notified to HMRC?

For options granted before 6 April 2027, by 6 July after the end of the tax year in which they were granted. Miss it and the options lose their EMI tax advantages. The scheme must be registered with HMRC’s online service before you can notify.

What happens if my director’s loan account is overdrawn at year-end?

If it isn’t repaid within nine months and one day of the year-end, the company pays section 455 tax on the balance, at 35.75% for loans made on or after 6 April 2026. The tax is refundable once the loan is repaid, but only after a delay. Loans over £10,000 can also create a taxable benefit.

How should a SaaS startup recognise subscription revenue?

Over the period the service is provided, not when the cash arrives. An annual subscription paid upfront is mostly deferred income at first and is released month by month. The revised FRS 102 Section 23 adds more structure for bundled deals and set-up fees from 2026.

How do I calculate my startup’s runway?

Divide the cash in the bank by your net monthly burn, meaning cash out minus cash in. Then run it again on your hiring plan and on a downside case where revenue stalls. The lowest of the three is the number to plan around.

Can founders do their own startup bookkeeping?

Yes, in the early months, if they’re disciplined and the software is set up properly. Have an accountant check the setup, then hand over once transaction volume grows, staff are hired or investors start asking for monthly numbers.

What will investors check in due diligence?

They’ll typically ask for:

• management accounts and deferred income;
• director’s loans;
• the cap table and option register;
• R&D claims;
• VAT and PAYE history;
• leases and finance agreements.

A startup that can produce clean, reconciled versions quickly signals control, and avoids extra warranties or price chips.

Building a startup finance function that survives a funding round

Most of what goes wrong in startup accounting is decided in the first year, not at the first audit. A personal card used once too often, a loan nobody wrote down, a subscription booked as cash, an R&D project nobody logged. By the time investors ask, rebuilding those is slow and expensive.

We work as the back office for UK accountancy practices with technology and startup portfolios. That means monthly startup bookkeeping with deferred income and director’s loan schedules built in, plus payroll for founders and first hires.

On top of that sit management accounts with runway reporting, and year-end accounts under the revised FRS 102, delivered ready to review. Standard jobs come back within five working days.

If you’d rather test it than take our word for it, send us one real startup file, ideally the one with the director’s loan account nobody has reconciled. We’ll rebuild the schedule, set up the deferred income and hand back a pack your reviewer can sign.

Start a free trial or talk to our IT and SaaS team.

Related reading: IT and SaaS accounting for UK practices | Outsourced management accounts | Outsourced bookkeeping services UK

This article is general guidance for UK accountancy practices and startup founders and is not a substitute for advice on a specific company. Tax rates, R&D and EMI rules, FRS 102 requirements and filing deadlines are those in force as at October 2026 and may change.