March 23, 2018 

AmosWEB means Economics with a Touch of Whimsy!

AmosWEBWEB*pediaGLOSS*aramaECON*worldCLASS*portalQUIZ*tasticPED GuideXtra CrediteTutorA*PLS
TOTAL-MARGINAL RULE: A mathematical connection between a marginal value is the slope of a curve of the corresponding total value stating that the marginal IS the slope of the total curve. If the total curve has a positive slope (that is, is upward sloping), then marginal is positive. If the total product has a negative slope (downward sloping), then marginal is negative. If the total curve has a zero slope (horizontal), then marginal is zero. Moreover, if the total curve has an increasing slope (becoming steeper), then the marginal is rising. If the total curve has a decreasing slope (becoming flatter), then the marginal is falling.

Visit the GLOSS*arama


The range of quantities of a factor that a firm is willing and able to sell at a range of factor prices. Supply by a firm is a phrase that is most relevant to the study of factor markets, especially when contrasted with supply to a firm. Supply by a firm puts the firm on the selling side of the factor market. Supply to a firm puts the firm on the buying side of the factor market.
The distinction between "supply by a firm" and "supply to a firm" is most important for produced factors of production, especially the vast array of capital goods. The importance comes from the possible confusion over which side of the factor market a firm is on. This confusion results as much as anything from the notion that firms are typically on the supply-side of the product markets and the demand-side of factor markets. However, firms also appear on the supply-side of factor markets.

To illustrate this notion of "supply by a firm," consider the production of Quadra 9000 computers by the innovative folks at Quadra DG Computer Works. Standard operating procedure for Quadra DG Computer Works is to produce Quadra 9000 computers according to the standard principles of production and cost (law of diminishing marginal returns, profit-maximization, etc.). It then supplies these computers to consumers, like Duncan Thurly, residing in households all over the economy, through product markets (stores, mail order, etc.). Quadra DG Computer Works does the supplying of Quadra 9000 computers and the relevant phrase is "supply by a firm."

The phrase "supply by a firm" is also relevant if Quadra DG Computer Works supplies Quadra 9000 computers as capital goods rather than consumer goods. When Quadra 9000 computers are used as capital goods and they are considered a factor of production. For example, Quadra 9000 computers are an important productive factor for cellular telephone communication services offered by Digital Distance Wireless Telecommunications, for the fabrication of Flex-Star Interactive Trophy Plaques, and for the automated assembly of OmniMotors XL GT 9000 Sports Coupe automobiles.

When Quadra DG Computer Works supplies Quadra 9000 computers to Digital Distance Wireless Telecommunications, Flex-Star Interactive Trophy Plaques, and OmniMotors XL GT 9000 Sports Coupe, then the relevant phrase is also "supply by a firm."

The phrase "supply to a firm," however, is relevant from the other side of this computer market. From the viewpoint of Digital Distance Wireless Telecommunications, computers are being supply TO, not FROM. They are the buyers in this factor market. This supply to a firm involves the "supply" of Quadra 9000 computers, with the "to a firm" being Digital Distance Wireless Telecommunications.

The distinction between "supply by a firm" and "supply to a firm" is particularly important in terms of market control. For a perfectly competitive seller, the supply by a firm, that is the firm's supply curve, is the firm's marginal cost curve above average variable cost. For a monopoly, in which the seller has complete control over the selling-side of the market, then the supply by a firm is whatever the monopoly supplies, which may or may not follow a standard positively-sloped supply curve. For imperfectly competitive firms, including oligopoly and monopolistic competition, supply by a firm is corresponding portions of the overall market supply controlled by each firm.

By way of comparison, for a perfectly competitive buyer, "supply to a firm" is a perfectly elastic, horizontal supply curve. For a monopsony, in which the buyer has complete control over the buying-side of the market, then the supply to a firm is the overall market supply, which is typically positively sloped. For imperfectly competitive firms, including oligopsony and monopsonistic competition, supply to a firm is corresponding portions of the overall market supply.


Recommended Citation:

SUPPLY BY A FIRM, AmosWEB Encyclonomic WEB*pedia,, AmosWEB LLC, 2000-2018. [Accessed: March 23, 2018].

Check Out These Related Terms...

     | supply to a firm | factor supply | factor supply curve | factor supply determinants | mobility | geographic mobility | occupational mobility |

Or For A Little Background...

     | supply | supply curve | market supply | product markets | resource markets | factor market analysis | marginal factor cost | marginal factor cost curve | factors of production | market control | market structures | circular flow |

And For Further Study...

     | marginal revenue product | marginal revenue product curve | factor demand | monopsony | bilateral monopoly | oligopsony | monopsonistic competition | aggregate supply | money supply |

Search Again?

Back to the WEB*pedia


[What's This?]

Today, you are likely to spend a great deal of time flipping through the yellow pages seeking to buy either a wall poster commemorating yesterday or pink cotton balls. Be on the lookout for mail order catalogs with hidden messages.
Your Complete Scope

This isn't me! What am I?

A communal society, a prime component of Karl Marx's communist philosophy, was advocated by the Greek philosophy Plato.
"It is not the straining for great things that is most effective; it is the doing of the little things, the common duties, a little better and better."

-- Elizabeth Stuart Phelps, Writer

Total Revenue
A PEDestrian's Guide
Xtra Credit
Tell us what you think about AmosWEB. Like what you see? Have suggestions for improvements? Let us know. Click the User Feedback link.

User Feedback

| AmosWEB | WEB*pedia | GLOSS*arama | ECON*world | CLASS*portal | QUIZ*tastic | PED Guide | Xtra Credit | eTutor | A*PLS |
| About Us | Terms of Use | Privacy Statement |

Thanks for visiting AmosWEB
Copyright ©2000-2018 AmosWEB*LLC
Send comments or questions to: WebMaster