The filings, valuation mechanics and tax reliefs of UK angel investing, defined plainly. Every term links to the tool or guide that puts it to work.
01
Filings & the register
Companies House
The UK's official company register. Every limited company must file incorporation details, accounts, confirmation statements and share allotments there - all public. Tero's free checker reads it live.
SH01
The “return of allotment” form filed when a company issues new shares, stating the number allotted and price paid. It is the filing that prices UK startup rounds - see how to read an SH01.
Confirmation statement (CS01)
The annual filing confirming a company's registered details, including its shareholder list - the closest thing to a public cap table for a private UK company.
PSC (person with significant control)
Anyone holding more than 25% of shares or voting rights, or otherwise exercising significant control. The PSC register shows who actually controls a company, which is not always who fronts it.
SIC code
The Standard Industrial Classification code a company selects to describe its activity. Self-declared and often generic - useful, not authoritative.
Micro-entity accounts
The minimal accounts format for the smallest companies: a condensed balance sheet, no profit-and-loss. This is why revenue is invisible for most early-stage UK companies - net assets and cash are often all the record shows.
Dormant company
A company with no significant accounting transactions in a period - it exists on paper but is not trading.
Strike-off
Removal of a company from the register - voluntary (directors apply) or compulsory (usually for failing to file). An active strike-off notice against a company you are about to fund is a conversation-ending red flag.
The Gazette
The official public record for statutory notices: strike-offs, winding-up petitions, insolvency. Checked in every Tero report.
Charge (MR01)
Security registered over a company's assets in favour of a lender. Normal for venture debt - but you want to know it exists and what it covers.
Director disqualification
A ban preventing a person from acting as a UK company director, recorded publicly. A hit on this register near a company you are considering should end the discussion.
02
Deals & valuation
Implied valuation
The valuation computed from a filed SH01: price per share × total shares after the round. What investors actually paid per the record - not the press-release number. The checker computes it for any UK company with priced filings.
Pre-money / post-money
Valuation before and after the new money. Post-money = pre-money + cash in. Confusing the two misstates everyone's ownership.
Priced round
A round with an agreed price per share (vs a convertible). In the UK these surface as SH01 filings with a stated premium - which is what makes them readable from the register.
Nominal value & share premium
Nominal value is a share's face value (often a fraction of a penny); the premium is what is paid above it. A large premium is the signature of a genuine external fundraise - allotments at nominal value usually mean founders or options, not a round.
Share class
A category of shares with defined rights (ordinary, preferred, growth). Different classes at different prices are one reason filed valuations need careful reading.
Dilution
The reduction in your percentage when new shares are issued. Every priced round dilutes non-participating holders - Tero's monitoring flags dilution events from new filings.
Cap table
Who owns what, across all share classes. For private UK companies the annual confirmation statement is the public approximation.
Convertible / ASA
An instrument (e.g. an advance subscription agreement) converting into shares at a future round, usually at a discount. Invisible in the filings until conversion - a gap to remember when reading a register-derived cap table.
Down round
A round priced below the previous price per share - visible in the filings when a new allotment undercuts the prior one.
Follow-on
A further investment into an existing portfolio company at a later round. Follow-on rates are one of the strongest cohort-level quality signals.
03
Tax & reliefs
EIS (Enterprise Investment Scheme)
30% income-tax relief on qualifying investments, up to £1m/tax year (£2m where the excess is knowledge-intensive), three-year minimum hold. Model the full effect in the calculator.
SEIS (Seed Enterprise Investment Scheme)
EIS's earlier-stage sibling: 50% relief on up to £200,000 per tax year, for very young qualifying companies.
EIS3 / SEIS3 certificate
The certificate the company issues, without which no relief can be claimed. The window closes five years after the 31 January following the tax year - see claim deadlines.
Loss relief
On failure, the at-risk portion (after income-tax relief) offsets income at your marginal rate. It is why a £10,000 EIS cheque risks £3,850, not £10,000 - the downside maths.
CGT deferral relief (EIS)
Reinvest a gain into EIS and the CGT bill is deferred until disposal (gain arising 36 months before to 12 months after the investment). Postponed, not cancelled.
SEIS reinvestment relief
Reinvest a gain into SEIS in the same tax year and half of it is exempt from CGT - permanently.
Business Relief & inheritance tax
Unquoted trading shares held two years qualify for IHT relief. From 6 April 2026 the 100% relief is capped at a per-estate allowance (revised to £2.5m in Dec 2025) with 50% above - and unquoted EIS shares ARE in scope, whatever some guides say. Details in the 2026 rules guide.
Knowledge-intensive company (KIC)
A company meeting HMRC's R&D-intensity conditions - unlocks the higher £2m EIS investor cap and larger company-side limits.
Advance assurance
HMRC's pre-raise confirmation that a company is likely to qualify for SEIS/EIS. Most sophisticated investors ask to see it before committing.
Carry-back
Treating this year's SEIS/EIS investment as made last tax year - using last year's allowance and liability.
04
Angel practice
Due diligence
Verifying a company's claims before investing, against independent sources. The staged process is in our due-diligence guide; the free checker runs the registry layer in seconds.
Term sheet
The non-binding summary of a deal's key terms: valuation, share rights, board seats, protections.
SPV / syndicate
A special-purpose vehicle pooling angels into one cap-table line, usually organised by a syndicate lead. One reason register-derived cap tables understate the number of underlying investors.
Lead investor
The investor who negotiates terms and runs diligence on behalf of a round's smaller cheques. If you are not the lead, understanding what the lead actually checked is part of your own diligence.
Portfolio monitoring
Tracking companies after the cheque: new filings, allotments and dilution, officer changes, strike-off notices, adverse news. This is Tero's watchful-eye layer - a standing agent per company.
See these terms in the wild: run the free checker on any UK company, or read the guides.