Sit in on your first angel call and the language can feel deliberately exclusionary. The founder talks about raising on a SAFE at a four pre, the lead mentions pro-rata, someone asks whether it's SEIS-eligible, and you're nodding along while quietly working out whether to admit you've lost the thread.
You don't need to. Almost none of it is complicated once the words are unpacked. The jargon clusters into three things: what the company is judged to be worth, what your money actually buys you, and how the UK tax system treats the whole arrangement. Get those three straight and the rest is detail. Here's the working vocabulary, grouped the way the terms come up in a deal.
What do the valuation terms mean?
Valuation is simply the price tag put on the company for the purposes of the round. It isn't an objective fact - it's a negotiated number, often more art than science at the earliest stages, where there may be little more than a team and a prototype to value.
The pairing that trips up almost every beginner is pre-money and post-money. Pre-money is what the company is reckoned to be worth before the new money arrives. Post-money is that figure plus the amount raised. A firm valued at £4 million pre-money that takes in £1 million is worth £5 million post-money, and the new investors collectively own £1 million of £5 million - 20%. Quote the wrong one and the same headline number implies a very different slice of the business, which is exactly why founders and investors are careful about which they mean.
A round is a single fundraising event. The early ones run roughly in sequence: a pre-seed or seed round (the first proper outside money, where angels live), then Series A and onward as institutional venture capital takes over. A down round is a raise at a lower valuation than the previous one - rarely good news, and worth understanding if you're already on the cap table.
What do the equity and ownership terms mean?
Equity is ownership, held as shares. The cap table - short for capitalisation table - is the register of who owns what: founders, employees, and every investor, with their percentages. When a deal is described as messy, a tangled cap table is often what's meant.
Dilution is the term newcomers fear and misread in equal measure. When a company issues new shares in a later round, everyone's existing percentage shrinks, because the same number of your shares now represents a smaller slice of a bigger pie. Owning 5% before a raise might leave you with 4% afterwards. That isn't theft and it isn't necessarily a loss - 4% of a company worth ten times more is the better outcome. Dilution only stings when the company isn't growing into the new shares it keeps printing.
Pro-rata rights are your option to put more money into future rounds to maintain your percentage and offset that dilution. An option pool (or ESOP) is a block of shares set aside for employees; it dilutes existing holders too, which is why where it sits in the maths - before or after the raise - is quietly contentious.
What do the deal-structure terms mean?
A term sheet is the short, mostly non-binding document that sets out the headline terms of an investment - valuation, amount, and the rights attached - before the long-form legal contracts are drawn up. It's the deal in summary.
The lead is the investor who negotiates that term sheet and usually does the heaviest due diligence - the work of checking the team, the market and the numbers before committing. Everyone else follows on, investing on the lead's terms, frequently through a syndicate that pools many small cheques into one line on the cap table. Backing a credible lead is how a lot of newer angels get access to deals, though it does mean leaning on someone else's judgement - worth interrogating, not swallowing whole.
Two instruments let a company take your money before fixing a valuation. A convertible loan note is a loan that converts into shares at the next priced round, often at a discount. A SAFE (Simple Agreement for Future Equity) does something similar without the debt mechanics. Both are common in the US. The UK wrinkle: a plain SAFE usually doesn't qualify for SEIS or EIS relief, because those schemes generally need shares issued at the time you invest - which is why many UK rounds use an advance subscription agreement or a straight priced round instead.
What do the UK tax-relief terms mean?
This is the genuinely British part of the vocabulary, and the part where getting the meaning wrong can cost real money. Three schemes come up constantly, and the figures below are from HMRC, current as of guidance updated 6 April 2026.
SEIS, EIS and the certificates
SEIS (the Seed Enterprise Investment Scheme) targets the very youngest companies and is the most generous: 50% income tax relief on up to £200,000 a tax year, a three-year minimum hold, capital gains exemption on the shares if you claimed the relief, loss relief if it fails, and a capital gains reinvestment relief worth 50% of a gain rolled into SEIS shares (on up to £100,000 of investment a year). Relief can be carried back to the previous tax year. On the company side, SEIS is for firms trading under three years, with fewer than 25 full-time-equivalent staff, gross assets under £350,000 at share issue, and a £250,000 lifetime SEIS cap. See HMRC's SEIS guidance on gov.uk.
EIS (the Enterprise Investment Scheme) is for slightly larger but still early-stage companies: 30% income tax relief on up to £1,000,000 a tax year, or £2,000,000 if at least £1,000,000 goes into knowledge-intensive companies (research-heavy firms that meet HMRC's tests). Same three-year hold, capital gains exemption, loss relief and carry-back, plus a capital gains deferral relief that postpones tax on a gain made elsewhere. The company-side caps are larger - broadly, gross assets up to £30 million before the shares are issued, fewer than 250 full-time-equivalent employees, within seven years of first commercial sale, up to £10 million raised across the venture-capital schemes in any 12-month period and up to £24 million over its lifetime, with higher limits for knowledge-intensive companies. Those company-side figures were adjusted for 2026, so confirm the number that applies to a specific deal on HMRC's EIS guidance on gov.uk.
Two pieces of paperwork tie it together. Advance assurance is HMRC's pre-investment sign-off that a round should qualify. After the shares are issued, the company sends each investor an SEIS3 or EIS3 certificate - the document you use to claim the relief through Self Assessment or directly with HMRC. You generally need to be a UK taxpayer for any of it to be worth having.
VCT
A VCT (Venture Capital Trust) is the hands-off option: a listed trust holding a diversified portfolio of small companies, so you buy shares in the trust rather than backing startups directly. It carries 20% income tax relief on up to £200,000 a year, tax-free dividends and no capital gains tax on the gains, with a longer five-year hold - and, unlike SEIS and EIS, no loss relief. The diversification is meant to do that job instead. See HMRC's investor guidance on gov.uk.
The jargon isn't a wall. It's three ideas wearing a lot of acronyms.
What about the investor labels - sophisticated, HNW, accredited?
Before most deals are shown to you, UK rules will ask you to certify as a high-net-worth or sophisticated investor - the Financial Conduct Authority's way of confirming you understand and can absorb the risk. These are self-certifications against set criteria, not a badge of expertise, and signing one is the gate most angels pass through before seeing a pitch. The American equivalent you'll hear in passing is an accredited investor; it's a different regime, but the idea is the same.
A note on the spirit of all of this rather than the letter: this article is general information, not financial or investment advice, and the rules - especially the tax figures - change. Before committing capital, take advice from an FCA-regulated adviser and confirm the current position with HMRC on gov.uk.
Frequently asked questions
What is the difference between pre-money and post-money valuation?
Pre-money is what a company is judged to be worth before new investment goes in. Post-money is the pre-money figure plus the new money raised. So a company valued at £4 million pre-money that raises £1 million is worth £5 million post-money, and the new investors own £1 million of £5 million, or 20%. The distinction matters because the same headline valuation can mean very different ownership depending on which one is being quoted.
What is a SAFE in angel investing?
A SAFE - Simple Agreement for Future Equity - is a short contract under which you give a company money now and receive shares later, usually when it next raises a priced round. It postpones agreeing a valuation. SAFEs are common in the US, but UK angels should note that a plain SAFE does not automatically qualify for SEIS or EIS tax relief, because those reliefs generally require shares to be issued at the time of investment. Many UK rounds use an advance subscription agreement or a priced round instead.
What does dilution mean for an angel investor?
Dilution is the reduction in your percentage ownership when a company issues new shares in later rounds. If you own 5% and the company raises again, your stake might fall to 4% even though the number of shares you hold has not changed - there are simply more shares in total. Dilution is not automatically bad: a smaller slice of a much larger company can be worth more. Pro-rata rights, where you can invest again to keep your percentage, are one way angels manage it.
What is the difference between a lead investor and a follow-on investor?
A lead investor sets the terms of a round - the valuation and the headline conditions - and usually does the bulk of the due diligence. Other angels then follow on, investing on the terms the lead has negotiated, often through a syndicate that appears as a single line on the cap table. Following a credible lead is how many newer angels get into deals, though the lead's judgement is doing a lot of the work, so it is worth understanding their reasoning rather than taking it on trust.
What are SEIS3 and EIS3 certificates?
They are the certificates a company sends you after your shares are issued, confirming the investment qualifies for SEIS or EIS relief. You use them to claim the relief through your Self Assessment tax return or by contacting HMRC. The company must first hold HMRC advance assurance - a pre-investment sign-off that the round should qualify. You generally need to be a UK taxpayer for the reliefs to be of use. Figures and rules are from gov.uk.