What can cause a leftward shift in the supply curve?

A leftward shift in the supply curve indicates a decrease in supply, which can result from an increase in production costs or a reduction in the number of suppliers in the market.

When input costs rise, it becomes more expensive for producers to manufacture their goods, leading them to supply less at each price level. This increased cost reduces profitability for existing firms, often causing them to decrease their output or even exit the market, contributing to the leftward shift.

Similarly, a decrease in the number of firms directly affects the overall supply in the market. If some firms exit the industry, the total quantity of goods supplied at any given price will decline, leading to a leftward shift.

Overall, both the increase in input costs and the reduction in the number of firms work together to reduce the quantity supplied at every price, thus confirming that a leftward shift in the supply curve is indeed caused by these factors.