Economics: Supply and the Market Supply Curve

Supply represents the other side of the market following the study of demand.
This topic focuses on the seller, the seller's specific incentives, and how these individual incentives result in the market supply curve.
There are direct parallels between the supply model and the demand model. Both involve economizing actors making decisions based on price and incentives.
A defining characteristic of the supply curve is its shape; while demand curves slope downward, supply curves look different because they represent the perspective of the producers.

To understand individual supply, the specific market for oil is used as a primary example.
Individual suppliers, such as ExxonMobil, change their production behavior based on the market price of a barrel of oil.
Higher extraction costs: As the market price increases, companies find it profitable to extract oil from more expensive or difficult sources. * Regular Wells: These are the standard, lowest-cost wells currently operational. * Deepwater Oil Wells: These are only drilled and operational when it is profitable, which occurs when the market price reaches a threshold of at least 70\,$ a barrel. Below this price, the cost of drilling cannot be covered.\n * **Arctic Circle Rigs:** Drilling above the Arctic Circle is even more expensive and only becomes profitable when the price exceeds 80\,$ a barrel.
Production Patterns: * Price < 70\,$:** Only regular wells are active; production is at its lowest.\n * **Price reaches 70\,$ - 79\,$:** Deepwater wells are turned on; more oil is produced.\n * **Price > 80\,$: Arctic Circle rigs become operational; all three sources are active, resulting in the highest production levels.
Summary of Individual Incentives: As the price goes up, the quantity supplied increases because higher prices justify the cost of using more expensive extraction methods. This behavior is nearly identical across major players like ExxonMobil and Chevron.

The market supply curve is the aggregate behavior of all individual suppliers in a given market.
To calculate market supply, one must pick a specific price and sum the individual quantities supplied by every seller at that specific price.
Hypothetical Market Data (Exxon and Chevron): * At 10\,$ per barrel:**\n * Chevron Quantity Supplied: 0\, ext{billion barrels}\n * Exxon Quantity Supplied: 0\, ext{billion barrels}\n * Market Total: 0 + 0 = 0\, ext{billion barrels}\n * **At 50\,$ per barrel: * Chevron Quantity Supplied: $0.8\,\text{billion barrels}$ * Exxon Quantity Supplied: $1.2\,\text{billion barrels}$ * Market Total: $0.8 + 1.2 = 2.0\,\text{billion barrels}$ * At 100\,$ per barrel:**\n * Chevron Quantity Supplied: 1.0\, ext{billion barrels}\n * Exxon Quantity Supplied: 1.5\, ext{billion barrels}\n * Market Total: 1.0 + 1.5 = 2.5\, ext{billion barrels}\n * **At 150\,$ per barrel: * Chevron Quantity Supplied: $1.1\,\text{billion barrels}$ * Exxon Quantity Supplied: $1.7\,\text{billion barrels}$ * Market Total: $1.1 + 1.7 = 2.8\,\text{billion barrels}$
The resulting graph is an upward-rising curve that represents every seller in the market together.

Quantity Supplied: The amount of a good that sellers are willing to sell at any given price. This refers to a specific point on the supply curve.
Supply Schedule: A table or list that reports the quantity supplied at different prices (e.g., the specific lists of production for Exxon, Chevron, or the total market).
Supply Curve: A graphical representation of the supply schedule; it plots the quantity supplied at different prices.
Market Supply Curve: The graph showing the relationship between the total quantity supplied and the market price, while holding all else equal.

Shifts occur when the variables in the ‑bucket of all else‑ (factors held constant when drawing the curve) change. This moves the entire curve to the right (increase) or left (decrease).
Input Prices: If costs like shipping/transportation become cheaper, sellers can afford to supply more oil at the same price, shifting supply to the right.
Technology: Improved technology makes production cheaper. For example, if drilling technology improves, expensive Arctic rigs might become profitable at 50\,$ instead of 80\,4. This increases quantity supplied at every price point, shifting the curve to the right.
Number and Scale of Sellers: Adding more sellers increases market supply. Conversely, fewer sellers decrease supply. * Example (Libya): Libya is a massive oil producer, outputting approximately $1,500,000\,\text{barrels per day}$ . During the civil war in March 2011 (3/11), their production shut down, causing the market supply curve to shift to the left.
Sellers' Expectations about the Future: Suppliers react today based on what they expect will happen tomorrow. * If sellers expect oil prices to ‑tank‑ (decrease significantly) in the future, they will try to sell as much as possible today while prices are still high. This results in an increase in supply (rightward shift) today.

Movement Along the Supply Curve: This is caused exclusively by a change in the price of the product itself, holding everything else constant.
Shift of the Supply Curve: This is caused by a change in one of the other factors (input prices, technology, etc.), not the price of the product.

Demand: Slopes downward because consumers buy more as price drops. * Mnemonic: ‑Demand to the ground.‑
Supply: Slopes upward because sellers want to sell more as price increases. * Mnemonic: ‑Supply to the sky.‑