Chapter 9Intermediate~8 min

Supply and demand

Why prices rise and fall in an auction.

A share price is simply the price at which the most recent trade happened. It is not calculated by a formula — it emerges from an ongoing auction between buyers who want to own the share and sellers who want to give it up.

When more people want to buy than sell at the current price, buyers must offer more to win the share, so the price tends to rise. When more want to sell than buy, sellers must accept less, so the price tends to fall. This is supply and demand.

A tug of war

  • Buyers compete on price to attract sellers — that pushes prices up.
  • Sellers compete on price to attract buyers — that pushes prices down.
  • The current price is where the two sides last agreed.
'Demand' means how many shares buyers want at a given price. 'Supply' means how many sellers are willing to part with at that price. As the price moves, both quantities change.

Fictional example: if positive news makes many investors want GreenLeaf Foods Ltd at once, but few owners want to sell, the eager buyers bid higher and the price rises. If owners rush to sell while buyers hold back, the price falls. The company itself did not change — only the balance of buyers and sellers did.

Supply, demand and price pressure

Prices move when the balance between willing buyers and willing sellers shifts. Explore how each side affects that balance.

120
80
60
40
Selling pressureBalancedBuying pressure
Supply score 32Upward pressureDemand score 72

Net pressure

+38.5%

Upward pressure

Strength of the tilt

38 / 100

How far the marker sits from the centre

This is a conceptual model of pressure, not a price predictor. Real prices also depend on news, expectations, earnings, interest rates and much more — which is why this lesson is about understanding the forces, not forecasting them.
Shift the balance of buyers and sellers and watch the price respond.

No predictions

This shows the mechanism, not a forecast. Predicting tomorrow's price is not something a simulator — or this course — can do. Prices overshoot and reverse for reasons nobody fully anticipates.

Key takeaways

  • A share price is the price of the most recent trade, set by buyers and sellers.
  • More eager buyers than sellers tends to push prices up; the reverse pushes them down.
  • The current price is where supply and demand last agreed.
  • A simulation explains the mechanism; it does not predict where prices will go.

Check your understanding

Every answer comes with an explanation — the goal is understanding, not a score.

Question 1 / 30%

What is a share price?

How was this lesson?

Ratings are tied to your account so we can tell which lessons land well. Sign in to leave one — it takes a second.

Sign in to rate