Funding, Dilution & The Cost of Capital
Every business needs money to start and to grow. That money has to come from somewhere. This section explains the two big ways to get it, what you give up to get it, and how to tell whether taking outside money is a smart move or a costly mistake. We start from zero. By the end you will understand cap tables, dilution, valuation math, and the financial scorecards investors use to judge you.
Bootstrapping vs raising money — the real tradeoff
Bootstrapping means funding the business yourself — from your savings, and from the money customers pay you. You take no outside investment. Raising money means bringing in outsiders (investors or lenders) who give you cash now.
People talk about this like it is a personality choice. It is not. It is a trade between four things:
| What you want | Bootstrapping gives you | Raising gives you |
|---|---|---|
| Control | You keep 100% — you decide everything | You share control with investors |
| Profit | All future profit is yours | You split future profit by ownership % |
| Speed | Slow — you can only spend what you earn | Fast — a big cash injection now |
| Risk | Lower (no debt to repay, no pressure to exit) | Higher (you owe results, must grow fast) |
Bootstrapping wins on control and profit. Raising wins on speed and scale. Neither is "better." The right answer depends on whether your market rewards getting big fast (then raise) or rewards being steady and profitable (then bootstrap).
Equity vs debt — the two kinds of money
There are exactly two ways to get outside money.
Equity means selling a slice of ownership of your company. The investor gives you cash and in return owns a percentage of the business forever (or until it is sold). You never "repay" equity. Instead, the investor makes money only if the company becomes valuable later.
Debt means borrowing money you must pay back, usually with interest (an extra fee for borrowing). A bank loan is debt. You keep 100% ownership, but you owe fixed payments whether business is good or bad.
| Equity | Debt | |
|---|---|---|
| Do you repay it? | No | Yes, with interest |
| Do you give up ownership? | Yes | No |
| What if the business fails? | Investor loses their money | You still owe the money |
| Best for | Risky, high-growth bets | Predictable cash flow to repay |
Dilution — giving away ownership %
Dilution means your ownership percentage going down because new shares were given to investors. Your slice of the pie gets thinner each time you raise equity.
The trick to understand: dilution is not always bad. A smaller slice of a much bigger pie can be worth far more than your whole original tiny pie.
Cap table basics
A cap table (short for "capitalization table") is just a list of who owns what percentage of the company. At the start it is simple — two founders, 50/50. After you raise money, investors get added as rows. The cap table is the official record of ownership, so keep it clean and accurate from day one.
SIMPLE CAP TABLE (before any raise) Owner Ownership --------- --------- Founder A 50% Founder B 50% --------- --------- TOTAL 100%
Pre-money and post-money valuation
Before anyone can buy a slice of your company, you both must agree what the whole company is worth. That agreed worth is the valuation. There are two versions, and confusing them is a classic founder mistake.
- Pre-money valuation = what the company is worth before the new investment goes in.
- Post-money valuation = what it is worth after the cash lands. It is simply pre-money plus the new money.
The core formulas:
Post-money = Pre-money + Investment
Investor % = Investment
----------------
Post-money
A full worked dilution example
- Post-money = $4,000,000 pre + $1,000,000 raised = $5,000,000.
- Investor owns = $1,000,000 ÷ $5,000,000 = 0.20 = 20%.
- Founders keep = 100% − 20% = 80%, split between them. If it was a 50/50 founder team, each founder now owns 40% (half of 80%).
This 20%-for-a-seed-round figure is no accident. Across the market, seed rounds typically cost founders somewhere in the high teens to around 20% of the company, and good advice is to try to stay under 25% per round. Giving away much more than that, round after round, leaves founders owning too little to stay motivated — which investors themselves dislike.
What investors look at financially
Investors are buying a piece of your future. To judge it, they look at a handful of numbers. (Several of these use ARR — Annual Recurring Revenue, the yearly value of subscriptions you can count on repeating.) Here are the big ones in plain English.
1. Growth rate
How fast revenue is rising, usually year over year. Fast growth signals a real market pulling your product. It is the single thing growth investors care about most early on.
2. Gross margin
Gross margin = the percentage of each sales dollar left after the direct cost of delivering the product. High margin means each new customer adds a lot of profit. Software businesses often target very high gross margins (commonly 70–80%+) because copies cost almost nothing to make. Low margin makes growth less valuable.
3. The Rule of 40
This is a quick health check for whether you are balancing growth and profit well. It says: growth rate % + profit margin % should be at least 40. The idea was popularized by venture capitalist Brad Feld in 2015, who called 40 "the minimum point of happiness." It uses recurring-revenue growth plus profit margin (often EBITDA margin).
Rule of 40: Growth % + Profit Margin % >= 40
4. Burn multiple
Net burn = how much cash you lose per period (money out minus money in). The burn multiple, popularized by investor David Sacks (it flips Bessemer's "efficiency score"), asks: how many dollars do you burn to add one dollar of new recurring revenue?
Burn Multiple = Net Burn
------------------
Net New ARR
| Burn multiple | What it means |
|---|---|
| Under 1x | Very efficient — make more than a dollar per dollar spent |
| 1x – 1.5x | Healthy |
| 1.5x – 2x | Acceptable for early, high-growth startups |
| 2x – 3x+ | Investors start to worry about discipline |
Lower is better. Earlier-stage companies are forgiven higher multiples; later-stage companies are expected to get efficient (often well under 1x).
5. Magic number
The magic number measures sales efficiency: for every $1 you spend on sales and marketing, how many dollars of new recurring revenue do you create (annualized)? A common formula compares the rise in revenue from one quarter to the next against the prior quarter's sales-and-marketing spend.
The widely cited rule of thumb (from investor Lars Leckie, 2008): above 0.75 is healthy — your machine turns marketing dollars into revenue efficiently, so "pour on the gas." Below 0.75, stop and fix the engine before spending more.
The cost of capital idea
Cost of capital is the price you pay to use someone else's money. Both debt and equity have a cost.
- The cost of debt is easy to see: the interest rate. Borrow at 10% and the cost is 10% a year.
- The cost of equity is hidden but usually higher: it is all the future profit you gave away forever. Equity investors take big risks, so they expect big returns — far more than a loan's interest.
When raising is right — and when it is wrong
Raising is usually right when:
- You have proof the business works (real customers, healthy gross margin) and money is the only thing stopping you from growing fast.
- Your market is winner-takes-most, so being first and biggest really matters.
- You need to build something expensive before revenue can exist (hardware, deep tech).
Raising is usually wrong when:
- You are raising to avoid finding out whether customers actually want the product. Money hides the problem; it does not fix it.
- The business can fund its own growth from profits — then why give away ownership?
- You do not yet know what you would do with the cash. Raising without a clear use just buys an expensive deadline.
Why understanding this protects you in negotiations
Investors do this every day. You might do it a few times in your life. That gap is where founders get hurt. When you can do the valuation math in your head, you can spot a bad deal instantly:
- You will know that pre-money vs post-money quietly shifts how much you give up — and ask which one they mean.
- You will know whether their "low" valuation is fair by checking your own Rule of 40, burn multiple, and magic number.
- You will know that every percent of dilution is permanent, so you can push back on giving away more than the round is worth.
- You will negotiate from data, not fear — and investors respect founders who understand their own numbers.
Sources: Rule of 40 (Brad Feld, 2015) — Wall Street Prep, Wikipedia; Burn Multiple (David Sacks / Bessemer) — Bottom Up by David Sacks, Wall Street Prep; SaaS Magic Number — The SaaS CFO, Wall Street Prep; Seed dilution & pre/post-money — Y Combinator, CRV.