First-cheque compliance: the UK registrations and deadlines a funded startup can't miss

The unglamorous list that keeps you out of trouble

None of this is exciting, and that's exactly why founders miss it. Registering for taxes and diarising Companies House dates has no dopamine in it — no product shipped, no customer won — so it slides down the list until a penalty letter arrives. The good news: almost every penalty here is avoidable, because they're triggered by missed dates, not by anything difficult. Spend an hour setting these up and diarising the deadlines, and you can forget about them.

Here's what a newly funded UK limited company needs to register for and file, roughly in the order it becomes relevant. Treat it as a checklist to work through once the money's landed.

1. Register for Corporation Tax

Every active UK limited company pays Corporation Tax on its profits, and you must tell HMRC that the company is active — "within scope of Corporation Tax" — within three months of starting to trade. The catch that surprises founders: "trading" doesn't mean "earning revenue". A startup is usually considered active once it's genuinely doing business — spending on building the product, hiring, buying equipment. So a pre-revenue funded startup almost always needs to register.

You'll get a deadline for filing your Company Tax Return (CT600) and paying any tax due, based on your accounting period. Pre-profit, you may owe nothing — but you still have to file. Full detail: What is Corporation Tax and when do I pay it →.

2. Set up PAYE if you're paying anyone — including yourself

The moment your company pays a salary — to a founder, an employee, anyone — it needs a PAYE scheme and has to report each payment to HMRC in real time (RTI) on or before payday. Many founders take a small salary from day one because it's tax-efficient; if that's you, register for PAYE before the first payment, not after.

This also covers National Insurance and, once you have staff, pension auto-enrolment obligations. Even a one-person payroll has to be done properly. See How to run payroll for one employee (or just yourself) → and What is RTI and how do I report it to HMRC →.

3. Decide on VAT — now, or diarise the trigger

Most freshly funded startups are below the VAT registration threshold and don't need to register on day one. But two situations change that. First, if your taxable turnover crosses the threshold (checked on a rolling 12-month basis) — or you expect it to within 30 days — registration becomes compulsory and the clock is tight. Second, some startups register voluntarily even while small, so they can reclaim the VAT on their spend; for a company spending a round on VAT-charging suppliers, that can be worth real money.

Whichever applies, the action now is: know your threshold, and either register or set a reminder to watch your rolling turnover. Don't discover you crossed it three months ago. See When do I have to register for VAT → and What is VAT and do I actually have to charge it →. If you do register, remember filing must be through Making Tax Digital–compatible software — see What is Making Tax Digital →.

4. Keep your Companies House filings on track

Separate from HMRC, Companies House has its own set of obligations from the day you incorporated:

• Confirmation statement — an annual check that your company details (directors, shareholders, registered office, people with significant control) are up to date. Due once a year from your incorporation date.
• Annual accounts — your company's financial statements, due nine months after your accounting year-end for a private company. Even a dormant or pre-revenue company files something.
• Share issue filings (SH01) — when you issue shares as part of the round, you file an SH01 to record the new allotment. This one's easy to forget in the excitement of closing. See How to issue shares and file an SH01 →.

Put all of these in a calendar now. Late Companies House filing carries automatic penalties that climb the longer you leave it. See Companies House filing: what's due and when →.

5. Handle SEIS/EIS so your investors get their relief

If your investors backed you partly for SEIS or EIS tax relief — extremely common for UK angels — the company has a job to do, and getting it wrong can cost your backers thousands. In outline: you need advance assurance or eligibility in place, you must issue the shares correctly, and after the shares are issued (and you've been trading or spending the money for the required period) you submit compliance statements — SEIS1 and EIS1 — to HMRC. HMRC then issues the certificates your investors need to actually claim their relief.

Miss or fumble this and your investors can't claim — which is a genuinely bad conversation and a reputational hit for your next raise. Get the timing and paperwork right and it's straightforward. See SEIS and EIS explained for founders → and the specifics in SEIS/EIS compliance after you raise →.

6. Keep the records that back all of this up

Every registration above assumes you can produce the underlying records when asked — what you earned, what you spent, who you paid, what you issued. UK companies are legally required to keep proper accounting records (generally for six years), and HMRC can ask to see them. This isn't extra work if your books are set up properly from day one; it's just the natural output of clean bookkeeping. See What records do I legally have to keep and for how long →.

Your compliance diary, in one place

Here's the short version to put in a calendar the day your round closes:

• Within 3 months of trading: register for Corporation Tax.
• Before the first salary: register for PAYE; report via RTI on each payday.
• When you issue the round's shares: file SH01; line up SEIS1/EIS1 for when eligibility allows.
• Rolling, always: watch your VAT threshold; register if you cross it or choose to voluntarily.
• Annually from incorporation: confirmation statement.
• 9 months after year-end: annual accounts.
• Ongoing: keep proper records (six years).

None of these is hard. They're missed only when they're not written down. Write them down now, while you remember, and this whole list becomes a non-event — which is exactly what compliance should be. For how it all fits into your wider first-month setup, see The 30-day finance setup checklist →.

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Ledgers keeps this list from becoming a problem — it registers what needs registering, tracks your VAT threshold, files MTD VAT, runs RTI payroll, and reminds you of every Companies House deadline, all in plain English. Compliance handled in the background while you build. Let Ledgers watch your deadlines → free to try.

Next in this guide: Set up your books to stay investor-ready from day one →

Frequently asked questions

What do I need to register for after incorporating a UK company?

At minimum, register for Corporation Tax with HMRC within three months of starting to trade. If you pay anyone a salary — including yourself — you also need a PAYE scheme. Register for VAT if you cross the threshold or choose to voluntarily. And keep your Companies House filings (confirmation statement, accounts, any share issue) on track.

Does a pre-revenue startup still have to register for Corporation Tax?

Usually yes. "Trading" for this purpose starts when the company is actively doing business — which typically includes spending on building the product, not just earning revenue. Once you're active, tell HMRC within three months.

What happens if I miss these deadlines?

HMRC and Companies House both charge automatic penalties for late registration and late filing, and repeated lateness can escalate. Most penalties are entirely avoidable — they happen because the dates weren't diarised, not because anything was hard. Put every deadline in a calendar now.

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