As a general rule, price of a commodity and its supply are directly related. It means, as price increases, the quantity supplied of the given commodity also rises and vice-versa. It happens because, at higher prices, there are greater chances of making a profit. It induces the firm to offer more for sale in the market.
As resources have alternative uses, the quantity supplied of a commodity depends not only on its price, but also on the prices of other commodities. An increase in the prices of other goods makes them more profitable in comparison to the given commodity. As a result, the firm shifts its limited resources from the production of the given commodity to the production of other goods.
When the amount payable to factors of production and cost of inputs increases, the cost of production also increases. This decreases the profitability. As a result, seller reduces the supply of the commodity. On the other hand, the decrease in prices of factors of production or inputs increases the supply due to the fall in the cost of production and the subsequent rise in profit margin.
Advanced and improved technology reduces the cost of production, which raises the profit margin. It induces the seller to increase the supply. However, technological degradation or complex and out-dated technology will increase the cost of production and it will lead to a decrease in supply.
An increase in taxes raises the cost of production and, thus, reduces the supply, due to the lower profit margin. On the other hand, tax concessions and subsidies increase the supply as they make it more profitable for the firms to supply goods.
Generally, the supply of a commodity increases only at higher prices as it fulfills the objective of profit maximization. However, with change in trend, some firms are willing to supply more even at those prices, which do not maximize their profits. The objective of such firms is to capture extensive markets and to enhance their status and prestige.