What a market price actually is

The handshake on the screen

Two strangers stand at a market stall. One has an old bicycle. One wants it. The seller says “£60.” The buyer says “£40.” They go back and forth and shake on £50. A bystander watching writes down: bicycle, £50.

That number — £50 — is the price. Not because the bicycle “is worth” £50 in some cosmic ledger. It’s £50 because that buyer and that seller, at that moment, agreed. Change either person and the number changes. A keener buyer pays £55. A desperate seller takes £45. The bicycle didn’t change. The handshake did.

A stock price is the same thing, sped up. It is the last point a willing buyer and a willing seller agreed. Nothing more solid than that sits underneath the number on the screen.

Inside the order book

In items 1 to 3 you saw a share is a slice of a real business. So why does its price jump around all day if the business hasn’t changed since breakfast?

Because the price isn’t a fact about the business. It’s a record of the latest handshake. To see how the handshake gets made, look at where shares actually trade: the order book. That’s just two lists kept side by side.

On one side, every bid — buyers and the most they’ll pay. On the other, every ask — sellers and the least they’ll take.

Say the book for one share looks like this:

• Buyers (bids): someone bids £99 for 100 shares · someone bids £98 for 200 · someone bids £97 for 500.
• Sellers (asks): someone asks £101 for 100 shares · someone asks £102 for 300 · someone asks £103 for 400.

Right now, nothing trades. The best buyer will pay £99. The cheapest seller wants £101. There’s a £2 gap between them, and a deal only happens when a bid meets an ask. So the two sides sit there, staring across the gap.

When the handshake prints

Now a new buyer walks in and is impatient. They don’t want to wait at £99 — they want the share now. So they accept the cheapest ask: £101 for 100 shares.

A trade prints. 100 shares change hands at £101. That £101 is now the last price — the most recent point a buyer and a seller actually agreed. The screen updates: £101.

Notice what just happened. The business is unchanged. No profit was earned, no factory built, no news broke. One person was willing to pay up, and the last price moved from “nothing trading near £100” to a printed £101. Price is made by who shows up and what they’ll accept — not by the thing itself.

Keep going. That impatient buyer wanted 300 shares, not 100. They’ve taken all 100 at £101. To get the rest, they accept the next ask: £102. Another print. Last price: £102. The cheapest seller left now wants £103. With one eager buyer, the last price climbed from £101 to £102, heading for £103. Add more eager buyers and it keeps climbing — each one reaches higher up the list of sellers to get filled.

Run it the other way. A holder needs cash today and sells into the bids: 100 shares hit the £99 buyer, then the next 200 hit the £98 buyer. Last price slides to £98. Pile on sellers and it falls further. Same book, opposite pressure.

The number is a consensus, not a fact

So the price is not the share’s “true value” sitting there waiting to be read off. It’s a snapshot of the most recent agreement, and it moves the instant the crowd of would-be buyers and sellers — and the prices they’ll accept — shifts.

This is the myth worth killing: price equals true worth. People say “the market says it’s worth £102” as if the market looked into the company’s soul. It didn’t. £102 is just where the last buyer and last seller happened to meet. The buyer might be wrong. The seller might be desperate. The next handshake, a second later, can be £101 or £104.

A useful test: ask “who agreed, and would a different crowd agree on a different number?” The answer is always yes. That’s why two equally smart people can look at the same share and one buys while the other sells — they’re not reading off a fact, they’re each making an offer.

The whole, and our small seat in it

In a moment you’ll work an order book yourself — place a bid, add a big buyer or a big seller, and watch the last price climb or fall as handshakes print.

Step back from one share. A whole market is millions of these handshakes a second, across thousands of businesses. Every printed price is a fleeting agreement between two strangers, instantly stale. The ticker looks authoritative — a single, official number — but it’s really the faint echo of the last two people who agreed, surrounded by a crowd who didn’t.

That should make anyone hold a price loosely. It isn’t the verdict of the world on what something is worth. It’s the last handshake, and you only ever see the number, never the two hands. We are all reading the same echo and mistaking it for the thing. Knowing that is the difference between trusting the screen and understanding it.