Ebrahim AlhamedFrameworks Library

m.01 · I · The Market Mechanism · Orientation · Gains from Trade

Why Trade Happens

Myatt · the most important market mechanism is the one you already live inside.

A trade happens whenever a buyer's valuation exceeds a seller's cost and they can agree on a price between the two. Every question in the course — market power, elasticity, regulation — rests on this one mechanism. Understand it and you understand why markets exist; miss it and you will always be shouting at prices. — after Myatt

Broker-mediated trade.

Buyers and sellers with private information. The broker matches them.

Network diagram Hub-and-spoke network with broker at the centre connected to: Buyer A, Seller A, Buyer B, Seller B. broker Buyer A Seller A Buyer B Seller B

The levers in the machine.

Price-Mediated Exchange · Myatt
buyer valuation · seller cost · negotiated price · gain from trade
Trade occurs when V > C. Surplus = V − C, split between parties.
Information Frictions · Myatt
private information · search cost · trust
Hidden information narrows the set of trades that happen. Brokers exist to fix that.

Any real-world deal you are running.

  1. State the buyer's valuation. What would they pay at most?
  2. State your cost. What is the lowest you would accept?
  3. Locate the price. Somewhere between the two. Bargaining power decides where.

Key reading · Production Choices in Frictionless Marketplaces · Myatt & Galeotti

What a frictionless market looks like.

No real market is frictionless — but every real market gets read against one that is. That is the whole point of the benchmark: it tells you where the friction sits, and how much of your margin lives there. Supply, demand and equilibrium prices all start from this reference, then deform.

Start with how a price emerges. Everything else is perturbation.

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