Fund Size and Cheque Size: Why a Fund's AUM Predicts Its Behaviour

One of the most useful questions to ask before pitching any fund is: how big is their current fund, and what cheque size does that imply? The answer reveals more about how they'll behave with you than any conversation will.

This article walks through the maths that connects fund size to cheque size, and what it means for which investors you should and shouldn't be pitching.

The core relationship

A fund deploys its capital across a portfolio over its life. Two numbers shape the cheque side of that:

• Number of investments. A typical fund makes 20–40 investments. Some go higher (50–80 for high-volume seed funds); a few go lower (10–15 for concentrated funds).
• Reserve ratio. Funds split their capital between initial cheques and follow-on capital ("reserves"). A common split is 40/60 — 40% goes into first cheques, 60% is held in reserve for follow-ons in winners.

From those, you can estimate the average initial cheque a fund will write:

Initial cheque size ≈ (Fund size × initial-cheque allocation) / number of investments

A few examples:

• $50m fund, 25 investments, 40% to initial cheques: $50m × 0.4 / 25 = $800k average initial cheque.
• $200m fund, 30 investments, 50% to initial cheques: $200m × 0.5 / 30 = $3.3m.
• $500m fund, 25 investments, 50% initial: $10m initial cheques.
• $2bn multi-stage, 25 deals, 50% initial: $40m average initial cheque.

These are averages. Real funds write a range — but the average is a strong predictor of where they'll spend most of their attention.

Why this maths matters to you

Three implications.

1. A fund can't write a "small" cheque if its maths doesn't work

A $2bn fund cannot meaningfully be moved by a $1m investment. Even if the company 100x's, the return is small relative to fund size. So large funds rarely get serious about small deals — even when individual partners are interested.

The exception: scout cheques and small "tracking" investments. These exist precisely so large funds can stay close to early companies without needing to deploy real capital. If a $2bn multi-stage offers a $250k tracking cheque at seed, recognise what it is: option value, not real engagement.

2. A fund's ownership requirement scales with fund size

To return a $200m fund 3x, you need $600m of proceeds. If a fund makes 30 investments and one or two of them produce most of the returns, those one or two need to deliver $200m+ each. To get $200m from a single deal, the fund typically needs ~5–10% ownership at exit.

Now scale up: a $1bn fund needs the same percentage ownership in larger outcomes — they need their winners to be unicorns or bigger. So a $1bn fund will require a larger ownership stake in your seed than a $50m fund would, because their downstream maths demands it.

This is why some funds say no to deals not because the deal is bad, but because they can't get the ownership they need. We unpack this in why VC returns are power-law.

3. Fund size predicts pace and process

Smaller funds tend to be:

• Faster to decide
• Less politically complex internally
• More willing to write conviction cheques on incomplete information
• Less brand-driven on portfolio markups

Larger funds tend to be:

• Slower
• More politically complex (partner sponsorship, IC, sometimes a vote)
• More demanding on due diligence
• Stronger on brand affiliation, customer credibility, hiring help

Neither is universally better. Match the pace and process to your needs.

How to estimate a fund's cheque-size sweet spot

When researching a fund, three signals:

1. Their portfolio's recent rounds. What size cheques are they writing today? A fund that wrote $1m cheques five years ago may write $5m cheques now after a much larger fund.
2. Their fund size and vintage. A $300m fund mid-deployment has more cheque firepower than a $300m fund late in deployment.
3. Their stated focus. Most funds publish a "we lead seeds with $1.5m–$3m cheques and reserve for follow-ons" statement. Take it at face value.

If a fund's sweet spot is $5m+ and you're raising $500k, they're not the right investor for this round. They might be the right one for your next round. Treat them accordingly.

Why it changes who leads vs follows

In a typical seed round:

• The lead writes the largest cheque, sets terms, often takes a board seat.
• Follow-ons participate at the lead's terms with smaller cheques.

A fund's size influences whether they want to be the lead. A fund that writes $3m cheques generally wants to lead a $5m round. A fund that writes $250k–$750k cheques generally follows. Pitching the latter as your lead is mismatched; pitching the former as a follow is asking them to play a game their maths doesn't support.

We have a piece on running a clean process: how to find investors for your startup.

Reserves and follow-ons

The "reserve" question matters more than founders realise. A fund that has 60% of its capital reserved for follow-ons is signalling that they want to keep buying more of the winners they've already backed. That's good for you if you're one of those winners — they'll lean into your A and B.

A fund that holds little or no reserves is often a "one-shot" investor. They write the seed cheque, then don't follow on. Some seed funds operate this way explicitly. It's not bad — just know it. Don't expect a $1m initial cheque from a fund with no reserves to suddenly become a $5m A cheque.

When in due diligence, you can directly ask: "What's your reserve ratio, and how do you think about follow-ons in this round?" Strong investors answer cleanly.

A practical filter

Before you put a fund on your target list, do this rough check:

• What's their fund size?
• How many investments will they make?
• Therefore, what's their average cheque?
• Does that match the cheque you need?

If the maths doesn't match, the fund is the wrong fund — even if their brand looks great. Don't burn meetings on funds whose mandates can't actually fund your round.

The investors you want are the ones whose fund maths makes them genuinely enthusiastic about a deal your size. Find them, and the rest of fundraising gets easier.