AccountsOS

We built an AI accountant. Accounting practices came to us. Finn runs the books on a real double-entry ledger. Reconciliation, VAT, month end, annual accounts, filed to HMRC with real receipts. A person reviews and signs. We built it for founders, then accountants asked to run it across their whole client book. That's the route to market: one practice relationship brings hundreds of businesses, and the first practices are already billing. Raising £1.25m to £1.5m pre-seed. The platform is built. Every pound goes to growth.

A practice's margin is staff time, and the software still makes people do the work. Bookkeeping, reconciliation, VAT and year-end prep are done by hand, in tools built to record the work rather than do it. Incumbents are bolting assistants onto twenty-year-old workflows and charging more for it. Xero raised UK prices again on 1 September 2026 and sells reconciliation and accounts-and-tax as add-ons. And the timing is forced. Making Tax Digital for Income Tax went mandatory in April 2026, 864,000 sole traders and landlords in the first wave. The free HMRC and Companies House filing service closed on 31 March 2026, so every small company now has to pick software this year.

AccountsOS is agent-on-ledger. Finn and its tools sit on one shared double-entry ledger, not a chat layer bolted onto someone else's books. - Finn does the bookkeeping, reconciliation, VAT returns, month-end close and annual accounts - Practice Mode runs that work across a whole client book, marks each client ready or blocked, and the accountant reviews and signs - Filings, money going out and deletes always need a human - Practices switch without ripping out Xero: connect read-only, Finn prepares the import, move the book in batches - Live through MCP, a public API, A2A, and apps in Claude and ChatGPT, so other agents can use the same books The test we build to: remove the dashboard and AccountsOS still works.

The UK is the proof market. 39,975 accounting, bookkeeping and tax firms (ONS 2025), 78 percent with four staff or fewer, and about 4.9 million companies on the Companies House register before sole traders and landlords. Bottom up: 1,000 UK practices at a 250-client book is 2.5 percent of UK firms and about £32.4m ARR at today's list pricing, before Ireland, Australia or founders. Capital has already priced the practice-led thesis. Pennylane raised $204m at a $4.25bn valuation in January 2026 selling accounting software through accountants in France. The UK has no AI-native equivalent yet. We run playbooks for 26 countries, with companies on the platform in 14.

- Live HMRC MTD VAT filings in production, with official receipts - Top 10 of 310 in the AI accounting software ranking (September 2026) - About six months from first commit to a live product filing real VAT returns - Over 200 sign-ups, about 40 of them accountants - Paying founders on the £20 plan, and two practices have started billing - Conversations with practices holding books of 200 to 600 clients, including New Zealand and Slovenia Revenue figures are shared in diligence, not published. These are founder-reported working figures for September 2026.

Paul Gosnell, founder. 20 years shipping digital products, founded and exited Tent & Bear, and took AccountsOS from first commit to a live product filing VAT with HMRC in six months, with coding agents rather than an engineering team. The round makes it full-time: everything else stops. It hires a growth lead, a performance marketer, three practice sales and partnership people and an accountant in residence. No support desk, no onboarding team, no engineering org. Finn and the agents do that work.

£1.25m to £1.5m. Growth only: the platform is built, live and filing VAT to HMRC. - 40 percent paid acquisition and marketing: performance marketing into the self-serve founder engine, a marketing lead, content at volume - 30 percent sales and practice partnerships: land the firm, move the book in batches, expand across it - 10 percent founder and agents: Paul full-time plus the AI spend that builds and runs the platform - 10 percent trust and compliance: security certification, an accountant in residence, HMRC and Companies House filing coverage - 10 percent reserve The 18-month plan is 60 practices at an average 200 live clients plus 3,000 paying founders, about £2.3m ARR. That's a plan derived from list pricing, not a forecast. Valuation and cheque size are discussed with Paul.