How and Why Market Prices Change, Changes in Supply
The supply of most products is also affected by a number of factors. Most important is the cost of producing products. If the price of natural resources, labor, capital, or entrepreneurship rises, sellers will make less profit and will not be as motivated to produce as many units as they were before the cost of production increased. On the other hand, when production costs fall, the amount producers are willing and able to sell increases.
Technological change also affects supply. A new invention or discovery can allow producers to make something that could not be made before. It could also mean that producers can make more of a product using the same or fewer inputs. The most dramatic example of technological change in the U.S. economy over the past few decades has been in the computer industry. In the 1990s, small computers that people carry to and from work each day were more powerful and many times less expensive than computers that filled entire rooms just 20 to 30 years earlier.
Opportunities to make profits by producing different goods and services also affect the supply of any individual product. Because many producers are willing to move their resources to completely different markets, profits in one part of the economy can affect the supply of almost any other product. For example, if someone running a barbershop decided to sign a contract to provide and operate the machines that clean runways at a large airport, this would decrease the supply of haircutting services and increase the supply of runway sweeping services.
When suppliers believe the price of the good or service they provide is going to rise in the future, they often wait to sell their product, reducing the current supply of the product. On the other hand, if they believe that the price is going to fall in the future, they try to sell more today, increasing the current supply. We see this behavior by large and small sellers. Examples include individuals who are thinking about selling a house or car, corn and wheat farmers deciding whether to sell or store their crops, and corporations selling manufactured products or reserves of natural resources.
Finally, the number of sellers in a market can also affect the level of supply. Generally, markets with a larger number of sellers are more competitive and have a greater supply of the product to be sold than markets with fewer sellers. But in some cases, the technology of producing a product makes it more efficient to produce large quantities at just a few production sites, or perhaps even at just one. For example, it would not make sense to have two or more water and sewage companies running pipes to every house and business in a city. And automobiles can be produced at a much lower cost in large plants than in small ones, because large plants can take greater advantage of assembly-line production methods.
All these different factors can lead to changes in what consumers demand and what producers supply. As a result, on any given day prices for some things will be rising and those for others will be falling. This creates opportunities for some individuals and firms, and problems for others. For example, firms producing goods for which the demand and the price are falling may have to lay off workers or even go out of business. But for the economy as a whole, allowing prices to rise and fall quickly in response to changes in any of the market forces that affect supply and demand offers important advantages. It provides an extremely flexible and decentralized system for getting goods and services produced and delivered to households while responding to a vast number of unpredictable changes.