Topic 7: Supply
1. Meaning
Supply is the quantity of a good or service that producers are willing and able to offer for sale at a given price in a given period of time.
2. Law of Supply
Other factors remaining constant, the higher the price of a good, the greater the quantity supplied; the lower the price, the smaller the quantity supplied.
Supply Schedule (Example)
| Price (KSh) | Quantity supplied |
|---|---|
| 10 | 10 |
| 20 | 30 |
| 30 | 50 |
| 40 | 70 |
| 50 | 90 |
The supply curve slopes upward from left to right.
Why the Curve Slopes Upward
- Higher prices mean higher profits, so producers supply more.
- New firms enter the market.
- Producers can cover rising costs of producing more units.
3. Determinants of Supply (Shift Factors)
- Cost of production (wages, raw materials, rent).
- Technology: reduces cost and raises output.
- Weather and natural factors (especially in farming).
- Taxes and subsidies.
- Number of sellers in the market.
- Price of related goods (producers may switch to a more profitable good).
- Government policy and regulations.
- Expectations about future prices.
- Transport and infrastructure.
4. Movement vs Shift of the Supply Curve
| Movement along the curve | Shift of the curve |
|---|---|
| Caused by a change in price | Caused by non-price factors |
| Change in quantity supplied | Change in supply |
- Increase in supply: shifts right. Decrease in supply: shifts left.
5. Exceptions to the Law of Supply
- Perishable goods: must be sold even if the price falls.
- Agricultural produce: supply depends on weather and seasons.
- Goods in fixed supply (e.g. rare paintings, land).
- Backward-bending supply of labour: workers may reduce hours as wages rise.
- Expectation of further price rise: sellers may hold back stock.
6. Types of Supply
- Joint supply (e.g. beef and hides)
- Competitive supply (e.g. wheat and maize on the same land)
- Composite supply
- Market supply
Quick Quiz
- Fall
- Rise, other factors constant
- Remain the same
- Disappear
Answer: Option 2- An increase in the cost of raw materials
- An improvement in technology
- A new tax on producers
- A drought for farm produce
Answer: Option 2- A tax
- A subsidy
- A tariff
- A fine
Answer: Option 2