What is Market Cap vs Valuation?
SibylVcAugust 4, 2026Clarity over convention
The Sibyl Un-Glossary
Some terms have been defined in many places, yet misinterpretations of them keep appearing in decks. At Sibyl, we’re doing the un-glossary instead: starting with what a term is often mistaken for, then working toward what it actually means. We hope it helps.
Market cap is one of the most common measures of company value.
It is also a number that most startups do not have.
Public companies have market capitalisations.
Private startups have valuations.
SAFEs may have valuation caps.
These numbers sound similar, but they describe different things.
What is market cap?
Market cap is calculated by multiplying a company’s current share price by the number of shares outstanding.
A company with one billion shares trading at $10 has a market cap of $10 billion.
The calculation is simple.
But that does not mean market cap is fixed or objectively correct.
The share price changes as investors react to financial results, future expectations, interest rates, competitors and wider market sentiment.
Market cap therefore tells you what the public market values a company at now.
It does not tell you what the company will be worth next year or what an acquirer would pay.
A SAFE cap is not a market cap
Suppose your startup raises money using a SAFE with a $10 million valuation cap.
That does not mean your company has a $10 million market cap.
It does not necessarily mean your company has been valued at exactly $10 million either.
The valuation cap sets the maximum valuation at which the SAFE can convert into shares during a future funding round.
If the SAFE has a $10 million cap and the next round is raised at a $20 million valuation, the SAFE investor may convert using the more favourable $10 million cap, depending on the SAFE terms.
The cap helps determine the investor’s conversion price and ownership.
It does not answer:
What is the company worth today?
It answers:
At what maximum valuation will this SAFE convert into equity?
SAFE caps are also not determined by business performance alone.
As Peter Walker of Carta has observed, founders with customers and revenue may raise at lower caps than founders with little more than an idea.
The difference may reflect investor demand, founder reputation, negotiating leverage and competition for the round.
A SAFE cap is partly a financing term and partly the outcome of a negotiation.
A startup valuation is not a market cap
Suppose an investor puts $2 million into a startup at an $8 million pre money valuation.
The resulting post money valuation is $10 million.
That is the valuation implied by the transaction.
But the company’s shares are not being continuously bought and sold in a public market.
The investor may also be buying preferred shares with rights that other shareholders do not have, such as liquidation preferences, board rights or pro rata rights.
The $10 million figure therefore does not mean that every share in the company could be sold at the same price.
A startup valuation is negotiated through a specific transaction.
A market cap is calculated from a publicly traded share price.
Share price is not market cap
A company trading at $100 per share is not necessarily worth more than one trading at $10 per share.
You also need to know how many shares each company has.
Twenty million shares trading at $100 produce a market cap of $2 billion.
One billion shares trading at $10 produce a market cap of $10 billion.
The first company has the higher share price.
The second has the higher market cap.
Why should founders care?
Most pre seed, seed and Series A startups do not have market caps.
Founders mainly encounter market cap when looking at public companies in their sector.
Those companies can provide a reference point for what investors value in mature businesses, but the comparison needs context.
A public company may have predictable revenue, audited financial statements, liquid shares and years of operating history.
A startup may be growing faster, but it carries far more uncertainty.
The useful question is not:
What is this public company’s market cap?
It is:
What revenue, growth, margins and level of maturity support that valuation, and what would need to become true for our startup to justify something similar?
What should founders call each number?
A SAFE with a $10 million cap has a $10 million SAFE valuation cap.
A company that raises $2 million at an $8 million pre money valuation has a $10 million post money valuation.
A public company’s share price multiplied by its outstanding shares gives its market cap.
The words sound similar.
The numbers answer different questions.
Most early stage startups have valuations.
They do not have market caps.
What it actually means
Market cap
Market cap, or market capitalization, is the total public market value of a company’s outstanding equity, calculated by multiplying its current share price by the number of shares outstanding.