Here's the order of operations most first-time angels get wrong. They agonise over the first cheque - the valuation, the deck, whether the founder can sell - and barely glance at the clause that decides whether they ever write a second one. That clause is the pro-rata right, and on the deals that actually return money, it often matters more than the entry price.
A pro-rata right (sometimes called a pre-emption right or participation right) is a contractual entitlement to invest in a company's next funding round so you can keep your percentage ownership at roughly the level you hold today. It lives in the shareholders' agreement or the subscription agreement. Follow-on investing is simply the act of putting more money into a company you already back. The right is the door; the follow-on is walking through it.
What does a pro-rata right actually do?
Every time a startup issues new shares - a fresh round, a bridge, an option-pool top-up - the existing slices of the pie get thinner. That's dilution, and it's normal; it's how a company funds its growth. A pro-rata right doesn't stop new shares being created. What it does is reserve you the option to buy enough of them to stand still.
Say you own 5% after a seed round. The company raises a Series A and issues new shares worth 25% of the enlarged company. Do nothing and your 5% becomes roughly 3.75%. With a pro-rata right, you can subscribe for enough of the new shares to hold the 5% - you write a cheque sized to your existing stake, on the same terms as the round. Decline, and you're diluted like everyone else. Here's the part people miss: the right is an option, not a shield. It protects your access to the round. Your ownership is only protected if you actually fund it.
The right is the door. The follow-on is walking through it.
Is follow-on investing the same as pro-rata?
The two terms get used interchangeably, and they shouldn't be. Follow-on investing is the broad activity: deploying more capital into a portfolio company at a later stage. The pro-rata right is the specific, negotiated mechanism that lets you do it on protected terms - up to the amount that maintains your percentage, with priority over outside money trying to get in.
You can follow on without a formal right, if the company chooses to let you. And you can hold a pro-rata right and decline to use it - which, frankly, you'll do most of the time. The point of the right isn't to exercise it everywhere. It's to have the choice on the two or three names that turn out to matter.
Why does this matter so much for angels?
Early-stage returns follow a power law: a small handful of investments carry the whole portfolio, and most of the rest go sideways or to zero. That maths has a sharp consequence for follow-on rights. The companies you'll most want to put more money into are precisely the ones that get hottest - and in a hot round, allocation is scarce. Founders and lead investors ration space. Your pro-rata right is what gives you a contractual claim to some of it, rather than a polite email saying the round is full.
There's a discipline point buried in here too. Follow-on capital is how professionals concentrate money behind the names that are working, instead of spreading thin and topping up the losers out of loyalty. The right gives you the option; the judgement about when to use it is the actual job.
What about super pro-rata rights?
A standard pro-rata right lets you hold your percentage. A super pro-rata right lets you buy more than your existing share in the next round - to increase your ownership, not just defend it. Lead investors and some seed funds push for these, because the whole strategy is to double down on winners early.
For individual angels they're uncommon, and founders usually resist them, because one investor buying extra means everyone else's pro-rata gets squeezed. If you ever see a super pro-rata term on a deal you're co-investing in, read it carefully - it tells you who really controls access to future rounds.
Where to look in the paperwork
Pro-rata language tends to sit in a handful of predictable places, and the detail is where the value leaks out:
- Who holds the right. Sometimes it's reserved for "major" investors above a minimum holding. Below that threshold, smaller angels get no right at all.
- How long you get to decide. A notice window of a couple of weeks is workable; a few days during a fast round can be impossible to fund in time.
- Whether it survives. Some rights fall away after the first qualifying round, or can be waived by a majority of shareholders - in which case yours can be voted away without your sign-off.
- Transfer and assignment. Whether you can pass the right to a fund or vehicle you later invest through.
How do SEIS and EIS interact with following on?
This is where UK angels have an edge worth understanding, and a trap worth avoiding. Tax reliefs attach to specific share issues, not to the company in perpetuity - so a follow-on round is a fresh test, judged on its own facts at the time those new shares are issued.
SEIS (the Seed Enterprise Investment Scheme) carries 50% income tax relief on up to £200,000 of investment per tax year, with a three-year minimum holding period. But the company-side window is narrow: under SEIS rules a company must be trading for less than three years, have fewer than 25 full-time-equivalent employees, hold gross assets under £350,000 at the share issue, and can raise no more than £250,000 in total under SEIS across its life. In practice that means SEIS is usually a once-only, very-early event - by the time a real follow-on round comes around, the company has often outgrown it. (gov.uk: SEIS guidance.)
EIS (the Enterprise Investment Scheme) is the one that does the heavy lifting on follow-ons. It offers 30% income tax relief on up to £1,000,000 of investment per tax year - or up to £2,000,000 if at least £1,000,000 of that goes into knowledge-intensive companies - again with a three-year minimum hold. The company-side limits are wide enough to span several rounds: per HMRC guidance current at the time of writing, a company must generally have gross assets of no more than £30 million before the share issue (and £35 million immediately after), be within seven years of its first commercial sale, employ fewer than 250 full-time-equivalent people, and can raise up to £10 million across the venture capital schemes in any 12-month period and up to £24 million over its lifetime. Knowledge-intensive companies qualify for extended limits on age and funding. These figures change - the April 2026 guidance lifted several of them - so check the current numbers before you rely on them. (gov.uk: EIS guidance.)
The practical upshot for follow-on investing: an EIS-relieved follow-on can be very efficient, provided the company still qualifies, still has advance assurance in place, and hasn't exhausted its raise limits when those new shares are issued. The company issues a fresh EIS3 certificate for that tranche, and you claim on that issue. Don't assume relief carries over automatically - confirm it for each round before you wire money.
A note we'll keep repeating: this is general editorial information, not financial, tax, or investment advice. The reliefs depend on your personal circumstances and on the company's eligibility at the time, and the rules shift. Speak to an FCA-regulated or suitably qualified tax adviser, and rely on the company's own SEIS3 or EIS3 paperwork, before committing capital.
The bottom line
Pro-rata rights are quiet on the term sheet and loud at exit. They decide whether you get to keep backing the one company in your portfolio that actually works, or whether you watch from the cap table as later, larger money takes the upside you spotted first. Read the clause as carefully as you read the valuation - and decide in advance which names you'd write a second cheque for.