Picture ten angel cheques, all the same size, all written with the same care. A reasonable expectation might be that they come back broadly in line with each other - some up, some down, averaging out to something sensible. That is almost never what happens. Five or six return less than you put in. Two or three roughly wash their face. And one, if you're fortunate, comes back at ten, twenty, fifty times the cheque - and quietly pays for all the others.
That distribution has a name. It's the power law, and it is the single most important idea in early-stage investing.
What is the power law in angel investing?
The power law describes returns that are concentrated rather than evenly distributed. In a normal, bell-curve world, most outcomes cluster around an average and extremes are rare. Angel portfolios don't behave like that. The majority of holdings return little or nothing; the returns that matter come from a small number of outliers that can each out-earn the entire rest of the book combined.
It's the same shape you see across venture capital generally, and the maths is unforgiving in a specific way: your downside on any single deal is capped at the cheque you wrote, but your upside is, in principle, unbounded. Lose and you lose one unit. Win big and you can make fifty. That asymmetry is the whole game, and it inverts a lot of ordinary investing instinct.
You can be wrong far more often than you're right and still come out ahead - if you're right by enough.
How do angels lose money?
Mostly by default. The blunt truth of early-stage investing is that the most common single outcome for an individual investment is a loss. Companies run out of runway. The market they bet on doesn't arrive, or arrives five years late. A founder team fractures. A larger competitor moves first. Sometimes the business is simply fine but never grows fast enough to be worth more than you paid.
Study after study of angel portfolios finds the same pattern: a large share of holdings return below cost, and a meaningful slice return nothing at all. This is not a sign that the investor picked badly. It's the texture of the asset class. The mistake newcomers make isn't losing on deals - that's guaranteed - it's losing on too few deals, so that no winner ever has the chance to show up.
How do angels actually make money, then?
From the outliers, and only really from the outliers. The arithmetic is worth sitting with. If nine of your ten investments go to zero and the tenth returns thirty times, you haven't lost - you've roughly tripled the money you put to work across the lot. The headline return on a successful angel portfolio is almost always a story about one or two holdings carrying the rest.
Which leads to the central, slightly counterintuitive discipline: you are not trying to be right often. You are trying to be in the room when something becomes very large, and to have written a cheque big enough that it moves the whole portfolio when it does. The question that matters at the point of investment isn't "is this likely to work?" - most things aren't - but "if this works, can it be enormous?"
Why does spreading bets matter so much?
Because if the returns live in a handful of rare winners, your odds of catching one in a single deal are poor. Concentrate everything in one or two companies and the most probable result, given the base rates, is that you lose. Spread the same capital across many investments and you raise the chance that at least one outlier lands in your book - the one that makes the maths work.
There's no magic number, and we're not going to hand you one; how many investments you can sensibly make follows from how much you can genuinely afford to lose, and that's a personal question best worked through with a regulated adviser. The structural point is simply that early-stage returns are lumpy, and a portfolio built to survive a lot of zeros looks very different from one built on a single conviction bet.
How do SEIS and EIS change the maths?
This is where the UK system does something genuinely useful. Two HMRC schemes, the Seed Enterprise Investment Scheme (SEIS) and the Enterprise Investment Scheme (EIS), are designed to reward backing young, qualifying companies - and they work on both ends of the power-law distribution. They return part of your money up front, and they cushion the losses that the distribution guarantees.
Relief on the way in
SEIS, aimed at the very earliest companies, gives 50% income tax relief on up to £200,000 invested per tax year, with a three-year minimum holding period. EIS, for the next rung up, gives 30% income tax relief on up to £1,000,000 per tax year - or £2,000,000 if at least £1,000,000 goes into knowledge-intensive companies (broadly, those doing heavy R&D) - also with a three-year hold. Relief on both can be carried back to the previous tax year. In plain terms: a meaningful slice of every qualifying cheque comes back as relief at the point of investment, before any company has succeeded or failed.
Relief when it goes wrong - and when it goes right
When a company fails, loss relief lets you set the capital you lost, after deducting the income tax relief already given, against your income or capital gains. So the true cost of a wipe-out is well below the headline cheque. On the winners, gains on SEIS and EIS shares are exempt from capital gains tax if held for three years or more and income tax relief was received - so the outliers that carry the portfolio aren't taxed on the way out. SEIS adds a capital gains reinvestment relief worth 50% of a gain reinvested into SEIS shares, on up to £100,000 a year; EIS offers capital gains deferral relief.
On the company side, EIS sits within defined limits - gross assets up to £30 million before the share issue (£35 million immediately after), an annual raise cap of £10 million across the venture capital schemes, a £24 million lifetime cap, fewer than 250 full-time-equivalent employees, and shares issued within seven years of the first commercial sale. Knowledge-intensive companies get higher ceilings, and some figures shifted from 6 April 2026, so check the current numbers in HMRC's guidance: gov.uk venture capital schemes (EIS). SEIS-qualifying companies must be trading for under three years, have fewer than 25 full-time-equivalent staff and gross assets under £350,000 at the share issue, and can raise up to £250,000 in total under the scheme.
None of this changes the underlying distribution. Most of your companies will still struggle; the reliefs don't make a bad business good. What they do is lower the cost of being wrong and leave the upside untaxed - which, in an asset class built on rare, large winners, tilts the long-run maths in the investor's favour. The schemes need advance assurance from HMRC before the investment, and the company issues SEIS3 or EIS3 certificates afterwards for you to claim. You generally need to be a UK taxpayer for any of it to be worth anything. The detail is in the HMRC guidance for investors.
What about time and getting your money out?
The power law plays out slowly. Until a company is sold or, far more rarely, floats, your shares are illiquid - there's no daily price and usually no ready buyer. The winners that carry a portfolio typically take somewhere between five and ten years to reach an exit, and plenty never do. The three-year SEIS and EIS holding periods are tax floors, not a guide to when money comes back. Patience isn't a virtue here so much as a precondition: the distribution only resolves over a long horizon, and the investor who needs the cash in eighteen months has misunderstood the instrument.
Understood properly, the power law is oddly freeing. It tells you to stop agonising over whether each individual company will survive - most won't - and to think instead about the shape of the whole portfolio: enough bets to give an outlier room to appear, cheques sized so a winner actually counts, and the patience to let a decade do its work. The losses aren't the failure mode. They're the cost of being in the game at all.
Frequently asked questions
What is the power law in angel investing?
The power law describes how returns in early-stage investing are concentrated rather than evenly spread. Instead of most companies producing a modest, average return, the great majority return little or nothing and a tiny number return many times the original cheque. Those few outliers can produce more profit than the entire rest of the portfolio combined, which is why angels build a spread of investments and judge the whole portfolio rather than any single deal.
How often do angel investments lose money?
Loss is the most common single outcome. Studies of angel portfolios consistently find that a large share of individual investments return less than the amount invested, and many return nothing at all. The headline portfolio returns that angels report come from the minority of holdings that succeed. This is the normal shape of early-stage investing, not a sign that something has gone wrong, which is why diversification across many deals matters so much.
How does SEIS or EIS loss relief work when a company fails?
If a company you backed under SEIS or EIS fails and you received income tax relief on the investment, loss relief lets you set the capital you lost, after deducting the relief already given, against your income or capital gains. SEIS also gives 50% income tax relief up front and EIS 30%, so a portion of each cheque is effectively returned at the point of investment. The reliefs reduce the cost of a loss; they do not remove it. Exact treatment depends on your circumstances, so take FCA-regulated advice.
How many companies should an angel back to spread the risk?
There is no fixed number, but the logic of the power law is that a single cheque is a poor way to invest, because the odds of catching one of the rare big winners in one deal are low. Building a wider spread of investments raises the chance that at least one outlier lands in your portfolio. How many you can sensibly make depends on how much you can genuinely afford to lose. This is general information, not advice on how to size or build a portfolio.